Maternal plasma angiogenic index-1 (placental growth factor/soluble vascular endothelial growth factor receptor-1) is a biomarker for the burden of placental lesions consistent with uteroplacental underperfusion: a longitudinal case-cohort study

A mitochondrial regulator protein, MNRR1, is elevated in the maternal blood of women with preeclampsia

OBJECTIVE

Preeclampsia, one of the most serious obstetric complications, is a heterogenous disorder resulting from different pathologic processes. However, placental oxidative stress and an anti-angiogenic state play a crucial role. Mitochondria are a major source of cellular reactive oxygen species. Abnormalities in mitochondrial structures, proteins, and functions have been observed in the placentae of patients with preeclampsia, thus mitochondrial dysfunction has been implicated in the mechanism of the disease. Mitochondrial nuclear retrograde regulator 1 (MNRR1) is a newly characterized bi-organellar protein with pleiotropic functions. In the mitochondria, this protein regulates cytochrome c oxidase activity and reactive oxygen species production, whereas in the nucleus, it regulates the transcription of a number of genes including response to tissue hypoxia and inflammatory signals. Since MNRR1 expression changes in response to hypoxia and to an inflammatory signal, MNRR1 could be a part of mitochondrial dysfunction and involved in the pathologic process of preeclampsia. This study aimed to determine whether the plasma MNRR1 concentration of women with preeclampsia differed from that of normal pregnant women.

METHODS

This retrospective case-control study included 97 women with preeclampsia, stratified by gestational age at delivery into early (<34 weeks, n = 40) and late (≥34 weeks, n = 57) preeclampsia and by the presence or absence of placental lesions consistent with maternal vascular malperfusion (MVM), the histologic counterpart of an anti-angiogenic state. Women with an uncomplicated pregnancy at various gestational ages who delivered at term served as controls (n = 80) and were further stratified into early (n = 25) and late (n = 55) controls according to gestational age at venipuncture. Maternal plasma MNRR1 concentrations were determined by an enzyme-linked immunosorbent assay.

RESULTS

1) Women with preeclampsia at the time of diagnosis (either early or late disease) had a significantly higher median (interquartile range, IQR) plasma MNRR1 concentration than the controls [early preeclampsia: 1632 (924-2926) pg/mL vs. 630 (448-4002) pg/mL, p = .026, and late preeclampsia: 1833 (1441-5534) pg/mL vs. 910 (526-6178) pg/mL, p = .021]. Among women with early preeclampsia, those with MVM lesions in the placenta had the highest median (IQR) plasma MNRR1 concentration among the three groups [with MVM: 2066 (1070-3188) pg/mL vs. without MVM: 888 (812-1781) pg/mL, p = .03; and with MVM vs. control: 630 (448-4002) pg/mL, p = .04]. There was no significant difference in the median plasma MNRR1 concentration between women with early preeclampsia without MVM lesions and those with an uncomplicated pregnancy (p = .3). By contrast, women with late preeclampsia, regardless of MVM lesions, had a significantly higher median (IQR) plasma MNRR1 concentration than women in the control group [with MVM: 1609 (1392-3135) pg/mL vs. control: 910 (526-6178), p = .045; and without MVM: 2023 (1578-8936) pg/mL vs. control, p = .01].

CONCLUSIONS

MNRR1, a mitochondrial regulator protein, is elevated in the maternal plasma of women with preeclampsia (both early and late) at the time of diagnosis. These findings may reflect some degree of mitochondrial dysfunction, intravascular inflammation, or other unknown pathologic processes that characterize this obstetrical syndrome.

Predictive Value of the sFlt-1/PlGF Ratio and Interleukin-6 for the Presence of Placental Lesions in Spontaneous Preterm Labor with Intact Membranes with Delivery within 7 Days

INTRODUCTION

The aim of the study was to identify predictive values of the soluble fms-like tyrosine kinase/placental growth factor (sFlt-1/PlGF) ratio and interleukin (IL)-6, assessed with a clinically available method in a large-volume biochemistry laboratory, in maternal blood, amniotic fluid, and umbilical cord blood for the presence of the placental lesions consistent with maternal vascular malperfusion (MVM) and acute histological chorioamnionitis (HCA), respectively.

METHODS

This retrospective study included 92 women with preterm labor with intact membranes (PTL) delivered within 7 days of admission with gestational ages between 22+0 and 34+6 weeks. The sFlt-1/PlGF ratio and IL-6 were assessed in stored samples of maternal serum, amniotic fluid, and umbilical cord serum using Elecsys® sFlt-1, PlGF, and IL-6 immunoassays.

RESULTS

Women with MVM had a higher sFlt-1/PlGF ratio in the maternal serum, compared to those without MVM (19.9 vs. 4.6; p < 0.0001), but not in the amniotic fluid or umbilical cord blood. A cut-off value of 8 for the sFlt-1/PlGF ratio in maternal serum was identified as optimal for predicting MVM in patients with PTL. Women with HCA had higher concentrations of IL-6 in maternal serum, compared to those without HCA (11.1 pg/mL vs. 8.4 pg/mL; p = 0.03), amniotic fluid (9,216 pg/mL vs. 1,423 pg/mL; p < 0.0001), and umbilical cord blood (20.7 pg/mL vs. 10.7 pg/mL, p = 0.002). Amniotic-fluid IL-6 showed the highest predictive value. A cut-off value of IL-6 concentration in the amniotic fluid of 5,000 pg/mL was found to be optimal for predicting HCA in PTL.

CONCLUSION

Maternal serum sFlt-1/PlGF and amniotic fluid IL-6 concentrations can be used for liquid biopsy to predict placental lesions in women with PTL who deliver within 7 days.

The placenta in fetal death: molecular evidence of dysregulation of inflammatory, proliferative, and fetal protective pathways

BACKGROUND

It is estimated that over 2 million cases of fetal death occur worldwide every year, but, despite the high incidence, several basic and clinical characteristics of this disorder are still unclear. Placenta is suggested to play a central role in fetal death. Placenta produces hormones, cytokines and growth factors that modulate functions of the placental-maternal unit. Fetal death has been correlated with impaired secretion of some of these regulatory factors.

OBJECTIVE

The aim of the present study was to evaluate, in placentas collected from fetal death, the gene expression of inflammatory, proliferative and protective factors.

STUDY DESIGN

Cases of fetal death in singleton pregnancy were retrospectively selected, excluding pregnancies complicated by fetal anomalies, gestational diabetes, intrauterine growth restriction and moderate to severe maternal diseases. A group of placentas collected from healthy singleton term pregnancies were used as controls. Groups were compared regarding maternal and gestational age, fetal sex and birthweight. Placental messenger RNA expression of inflammatory (interleukin 6), proliferative (activin A, transforming growth factor β1) and regulatory (vascular endothelial growth factor, vascular endothelial growth factor receptor 2, ATP-binding cassette transporters (ABC) ABCB1 and ABCG2, sphingosine 1-phosphate signaling pathway) markers was conducted using real-time polymerase chain reaction. Statistical analysis and graphical representation of the data were performed using the GraphPad Prism 5 software. For the statistical analysis, Student's t test was used, and P values<.05 were considered significant.

RESULTS

Placental mRNA expression of interleukin 6 and vascular endothelial growth factor receptor 2 resulted significantly higher in the fetal death group compared to controls (P<.01), while activin A, ABCB1, and ABCG2 expression resulted significantly lower (P<.01). A significant alteration in the sphingosine 1-phosphate signaling pathway was found in the fetal death group, with an increased expression of the specific receptor isoforms sphingosine 1-phosphate receptor 1, 3, and 4 (sphingosine 1-phosphate1, sphingosine 1-phosphate3, sphingosine 1-phosphate4) and of sphingosine kinase 2, 1 of the enzyme isoforms responsible for sphingosine 1-phosphate synthesis (P<.01).

CONCLUSION

The present study confirmed a significantly increased expression of placental interleukin 6 and vascular endothelial growth factor receptor 2 mRNA, and for the first time showed an increased expression of sphingosine 1-phosphate receptors and sphingosine kinase 2 as well as a decreased expression of activin A and of selected ATP-binding cassette transporters, suggesting that multiple inflammatory and protective factors are deranged in placenta of fetal death.

Genetic Associations with Placental Proteins in Maternal Serum Identify Biomarkers for Hypertension in Pregnancy

Background

Preeclampsia is a complex syndrome that accounts for considerable maternal and perinatal morbidity and mortality. Despite its prevalence, no effective disease-modifying therapies are available. Maternal serum placenta-derived proteins have been in longstanding use as markers of risk for aneuploidy and placental dysfunction, but whether they have a causal contribution to preeclampsia is unknown.

Objective

We aimed to investigate the genetic regulation of serum placental proteins in early pregnancy and their potential causal links with preeclampsia and gestational hypertension.

Study design

This study used a nested case-control design with nulliparous women enrolled in the nuMoM2b study from eight clinical sites across the United States between 2010 and 2013. The first- and second-trimester serum samples were collected, and nine proteins were measured, including vascular endothelial growth factor (VEGF), placental growth factor, endoglin, soluble fms-like tyrosine kinase-1 (sFlt-1), a disintegrin and metalloproteinase domain-containing protein 12 (ADAM-12), pregnancy-associated plasma protein A, free beta-human chorionic gonadotropin, inhibin A, and alpha-fetoprotein. This study used genome-wide association studies to discern genetic influences on these protein levels, treating proteins as outcomes. Furthermore, Mendelian randomization was used to evaluate the causal effects of these proteins on preeclampsia and gestational hypertension, and their further causal relationship with long-term hypertension, treating proteins as exposures.

Results

A total of 2,352 participants were analyzed. We discovered significant associations between the pregnancy zone protein locus and concentrations of ADAM-12 (rs6487735, P= 3.03×10 -22 ), as well as between the vascular endothelial growth factor A locus and concentrations of both VEGF (rs6921438, P= 7.94×10 -30 ) and sFlt-1 (rs4349809, P= 2.89×10 -12 ). Our Mendelian randomization analyses suggested a potential causal association between first-trimester ADAM-12 levels and gestational hypertension (odds ratio=0.78, P= 8.6×10 -4 ). We also found evidence for a potential causal effect of preeclampsia (odds ratio=1.75, P =8.3×10 -3 ) and gestational hypertension (odds ratio=1.84, P =4.7×10 -3 ) during the index pregnancy on the onset of hypertension 2-7 years later. The additional mediation analysis indicated that the impact of ADAM-12 on postpartum hypertension could be explained in part by its indirect effect through gestational hypertension (mediated effect=-0.15, P= 0.03).

Conclusions

Our study discovered significant genetic associations with placental proteins ADAM-12, VEGF, and sFlt-1, offering insights into their regulation during pregnancy. Mendelian randomization analyses demonstrated evidence of potential causal relationships between the serum levels of placental proteins, particularly ADAM-12, and gestational hypertension, potentially informing future prevention and treatment investigations.

Preeclampsia at term: evidence of disease heterogeneity based on the profile of circulating cytokines and angiogenic factors

BACKGROUND

Intravascular inflammation and an antiangiogenic state have been implicated in the pathophysiology of preeclampsia. On the basis of the profiles of their angiogenic/antiangiogenic factors, women with preeclampsia at term may be classified into 2 subgroups with different characteristics and prevalence of adverse outcomes. This study was undertaken to examine whether these 2 subgroups of preeclampsia at term also show differences in their profiles of intravascular inflammation.

OBJECTIVE

This study aimed to determine the plasma profiles of cytokines and chemokines in women with preeclampsia at term who had a normal or an abnormal angiogenic profile.

STUDY DESIGN

A nested case-control study was conducted to include women classified into 3 groups: women with an uncomplicated pregnancy (n=213) and women with preeclampsia at term with a normal (n=55) or an abnormal (n=41) angiogenic profile. An abnormal angiogenic profile was defined as a plasma ratio of placental growth factor and soluble fms-like tyrosine kinase-1 multiple of the median <10th percentile for gestational age. Concentrations of cytokines were measured by multiplex immunoassays.

RESULTS

Women with preeclampsia at term and an abnormal angiogenic profile showed evidence of the greatest intravascular inflammation among the study groups. These women had higher plasma concentrations of 5 cytokines (interleukin-6, interleukin-8, interleukin-12/interleukin-23p40, interleukin-15, and interleukin-16) and 7 chemokines (eotaxin, eotaxin-3, interferon-γ inducible protein-10, monocyte chemotactic protein-4, macrophage inflammatory protein-1β, macrophage-derived chemokine, and thymus and activation-regulated chemokine compared to women with an uncomplicated pregnancy. By contrast, women with preeclampsia at term and a normal angiogenic profile, compared to women with an uncomplicated pregnancy, had only a higher plasma concentration of monocyte chemotactic protein-4. A correlation between severity of the antiangiogenic state, blood pressure, and plasma concentrations of a subset of cytokines was observed.

CONCLUSION

Term preeclampsia can be classified into 2 clusters. One is characterized by an antiangiogenic state coupled with an excessive inflammatory process, whereas the other has neither of these features. These findings further support the heterogeneity of preeclampsia at term and may explain the distinct clinical outcomes.

Pathogenesis and Physiologic Mechanisms of Neonatal Pulmonary Hypertension: Preclinical Studies

Neonatal pulmonary hypertension (PH) is a devastating disorder of the pulmonary vasculature characterized by elevated pulmonary vascular resistance and mean pulmonary arterial pressure. Occurring predominantly because of maldevelopment or maladaptation of the pulmonary vasculature, PH in neonates is associated with suboptimal short-term and long-term outcomes because its pathobiology is unclear in most circumstances, and it responds poorly to conventional pulmonary vasodilators. Understanding the pathogenesis and pathophysiology of neonatal PH can lead to novel strategies and precise therapies. The review is designed to achieve this goal by summarizing pulmonary vascular development and the pathogenesis and pathophysiology of PH associated with maladaptation, bronchopulmonary dysplasia, and congenital diaphragmatic hernia based on evidence predominantly from preclinical studies. We also discuss the pros and cons of and provide future directions for preclinical studies in neonatal PH.

Proteomic profile of extracellular vesicles in maternal plasma of women with fetal death

OBJECTIVES

Fetal death is a complication of pregnancy caused by multiple etiologies rather than being the end-result of a single disease process. Many soluble analytes in the maternal circulation, such as hormones and cytokines, have been implicated in its pathophysiology. However, changes in the protein content of extracellular vesicles (EVs), which could provide additional insight into the disease pathways of this obstetrical syndrome, have not been examined. This study aimed to characterize the proteomic profile of EVs in the plasma of pregnant women who experienced fetal death and to evaluate whether such a profile reflected the pathophysiological mechanisms of this obstetrical complication. Moreover, the proteomic results were compared to and integrated with those obtained from the soluble fraction of maternal plasma.

METHODS

This retrospective case-control study included 47 women who experienced fetal death and 94 matched, healthy, pregnant controls. Proteomic analysis of 82 proteins in the EVs and the soluble fractions of maternal plasma samples was conducted by using a bead-based, multiplexed immunoassay platform. Quantile regression analysis and random forest models were implemented to assess differences in the concentration of proteins in the EV and soluble fractions and to evaluate their combined discriminatory power between clinical groups. Hierarchical cluster analysis was applied to identify subgroups of fetal death cases with similar proteomic profiles. A p-value of <.05 was used to infer significance, unless multiple testing was involved, with the false discovery rate controlled at the 10% level (q < 0.1). All statistical analyses were performed by using the R statistical language and environment-and specialized packages.

RESULTS

Nineteen proteins (placental growth factor, macrophage migration inhibitory factor, endoglin, regulated upon activation normal T cell expressed and presumably secreted (RANTES), interleukin (IL)-6, macrophage inflammatory protein 1-alpha, urokinase plasminogen activator surface receptor, tissue factor pathway inhibitor, IL-8, E-Selectin, vascular endothelial growth factor receptor 2, pentraxin 3, IL-16, galectin-1, monocyte chemotactic protein 1, disintegrin and metalloproteinase domain-containing protein 12, insulin-like growth factor-binding protein 1, matrix metalloproteinase-1(MMP1), and CD163) were found to have different plasma concentrations (of an EV or a soluble fraction) in women with fetal death compared to controls. There was a similar pattern of change for the dysregulated proteins in the EV and soluble fractions and a positive correlation between the log₂-fold changes of proteins significant in either the EV or the soluble fraction (ρ = 0.89, p < .001). The combination of EV and soluble fraction proteins resulted in a good discriminatory model (area under the ROC curve, 82%; sensitivity, 57.5% at a 10% false-positive rate). Unsupervised clustering based on the proteins differentially expressed in either the EV or the soluble fraction of patients with fetal death relative to controls revealed three major clusters of patients.

CONCLUSION

Pregnant women with fetal death have different concentrations of 19 proteins in the EV and soluble fractions compared to controls, and the direction of changes in concentration was similar between fractions. The combination of EV and soluble protein concentrations revealed three different clusters of fetal death cases with distinct clinical and placental histopathological characteristics.

Bronchopulmonary dysplasia - associated pulmonary hypertension: An updated review

Bronchopulmonary dysplasia (BPD) is the leading cause of chronic lung disease in infants and the commonest complication of prematurity. Advances in respiratory and overall neonatal care have increased the survival of extremely low gestational age newborns, leading to the continued high incidence of BPD. Pulmonary hypertension (PH) represents the severe form of the pulmonary vascular disease associated with BPD, and affects almost one-third of infants with moderate to severe BPD. PH responds suboptimally to pulmonary vasodilators and increases morbidity and mortality in BPD infants. An up-to-date knowledge of the pathogenesis, pathophysiology, diagnosis, treatment, and outcomes of BPD-PH can be helpful to develop meaningful and novel strategies to improve the outcomes of infants with this disorder. Therefore, our multidisciplinary team has attempted to thoroughly review and summarize the latest advances in BPD-PH in preventing and managing this morbid lung disorder of preterm infants.

Directive clinique no 442 : Retard de croissance intra-utérin : Dépistage, diagnostic et prise en charge en contexte de grossesse monofœtale

OBJECTIF

Le retard de croissance intra-utérin est une complication obstétricale fréquente qui touche jusqu'à 10 % des grossesses dans la population générale et qui est le plus souvent due à une pathologie placentaire sous-jacente. L'objectif de la présente directive clinique est de fournir des déclarations sommaires et des recommandations pour appuyer un protocole clinique de dépistage, diagnostic et prise en charge du retard de croissance intra-utérin pour les grossesses à risque ou atteintes.

POPULATION CIBLE

Toutes les patientes enceintes menant une grossesse monofœtale. BéNéFICES, RISQUES ET COûTS: La mise en application des recommandations de la présente directive devrait améliorer la compétence des cliniciens quant à la détection du retard de croissance intra-utérin et à la réalisation des interventions indiquées. DONNéES PROBANTES: La littérature publiée a été colligée par des recherches effectuées jusqu'en septembre 2022 dans les bases de données PubMed, Medline, CINAHL et Cochrane Library en utilisant un vocabulaire contrôlé au moyen de termes MeSH pertinents (fetal growth retardation and small for gestational age) et de mots-clés (fetal growth, restriction, growth retardation, IUGR, FGR, low birth weight, small for gestational age, Doppler, placenta, pathology). Seuls les résultats de revues systématiques, d'essais cliniques randomisés ou comparatifs et d'études observationnelles ont été retenus. La littérature grise a été obtenue par des recherches menées dans des sites Web d'organismes s'intéressant à l'évaluation des technologies dans le domaine de la santé et d'organismes connexes, dans des collections de directives cliniques, des registres d'essais cliniques et des sites Web de sociétés de spécialité médicale nationales et internationales. MéTHODES DE VALIDATION: Les auteurs ont évalué la qualité des données probantes et la force des recommandations en utilisant le cadre méthodologique GRADE (Grading of Recommendations Assessment, Development and Evaluation). Voir l'annexe A en ligne (tableau A1 pour les définitions et tableau A2 pour l'interprétation des recommandations fortes et conditionnelles [faibles]). PROFESSIONNELS CONCERNéS: Obstétriciens, médecins de famille, infirmières, sages-femmes, spécialistes en médecine fœto-maternelle, radiologistes et autres professionnels de la santé qui prodiguent des soins aux patientes enceintes. RéSUMé POUR TWITTER: Mise à jour de la directive sur le dépistage, le diagnostic et la prise en charge du retard de croissance intra-utérin pour les grossesses à risque ou atteintes. DÉCLARATIONS SOMMAIRES: RECOMMANDATIONS: Prédiction du retard de croissance intra-utérin Prévention du retard de croissance intra-utérin Détection du retard de croissance intra-utérin Examens en cas de retard de croissance intra-utérin soupçonné Prise en charge du retard de croissance intra-utérin précoce Prise en charge du retard de croissance intra-utérin tardif Prise en charge du post-partum et consultations préconception.

Guideline No. 442: Fetal Growth Restriction: Screening, Diagnosis, and Management in Singleton Pregnancies

OBJECTIVE

Fetal growth restriction is a common obstetrical complication that affects up to 10% of pregnancies in the general population and is most commonly due to underlying placental diseases. The purpose of this guideline is to provide summary statements and recommendations to support a clinical framework for effective screening, diagnosis, and management of pregnancies that are either at risk of or affected by fetal growth restriction.

TARGET POPULATION

All pregnant patients with a singleton pregnancy.

BENEFITS, HARMS, AND COSTS

Implementation of the recommendations in this guideline should increase clinician competency to detect fetal growth restriction and provide appropriate interventions.

EVIDENCE

Published literature in English was retrieved through searches of PubMed or MEDLINE, CINAHL, and The Cochrane Library through to September 2022 using appropriate controlled vocabulary via MeSH terms (fetal growth retardation and small for gestational age) and key words (fetal growth, restriction, growth retardation, IUGR, FGR, low birth weight, small for gestational age, Doppler, placenta, pathology). Results were restricted to systematic reviews, randomized controlled trials/controlled clinical trials, and observational studies. Grey literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALIDATION METHODS

The authors rated the quality of evidence and strength of recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. See online Appendix A (Table A1 for definitions and Table A2 for interpretations of strong and conditional [weak] recommendations).

INTENDED AUDIENCE

Obstetricians, family physicians, nurses, midwives, maternal-fetal medicine specialists, radiologists, and other health care providers who care for pregnant patients.

TWEETABLE ABSTRACT

Updated guidelines on screening, diagnosis, and management of pregnancies at risk of or affected by FGR.

SUMMARY STATEMENTS

RECOMMENDATIONS: Prediction of FGR Prevention of FGR Detection of FGR Investigations in Pregnancies with Suspected Fetal Growth Restriction Management of Early-Onset Fetal Growth Restriction Management of Late-Onset FGR Postpartum management and preconception counselling.

Accuracy of placental growth factor alone or in combination with soluble fms-like tyrosine kinase-1 or maternal factors in detecting preeclampsia in asymptomatic women in the second and third trimesters: a systematic review and meta-analysis

OBJECTIVE

This study aimed to: (1) identify all relevant studies reporting on the diagnostic accuracy of maternal circulating placental growth factor) alone or as a ratio with soluble fms-like tyrosine kinase-1), and of placental growth factor-based models (placental growth factor combined with maternal factors±other biomarkers) in the second or third trimester to predict subsequent development of preeclampsia in asymptomatic women; (2) estimate a hierarchical summary receiver-operating characteristic curve for studies reporting on the same test but different thresholds, gestational ages, and populations; and (3) select the best method to screen for preeclampsia in asymptomatic women during the second and third trimester of pregnancy by comparing the diagnostic accuracy of each method.

DATA SOURCES

A systematic search was performed through MEDLINE, Embase, CENTRAL, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform databases from January 1, 1985 to April 15, 2021.

STUDY ELIGIBILITY CRITERIA

Studies including asymptomatic singleton pregnant women at >18 weeks' gestation with risk of developing preeclampsia were evaluated. We included only cohort or cross-sectional test accuracy studies reporting on preeclampsia outcome, allowing tabulation of 2×2 tables, with follow-up available for >85%, and evaluating performance of placental growth factor alone, soluble fms-like tyrosine kinase-1- placental growth factor ratio, or placental growth factor-based models. The study protocol was registered on the International Prospective Register Of Systematic Reviews (CRD 42020162460).

METHODS

Because of considerable intra- and interstudy heterogeneity, we computed the hierarchical summary receiver-operating characteristic plots and derived diagnostic odds ratios, β, θi, and Λ for each method to compare performances. The quality of the included studies was evaluated by the QUADAS-2 tool.

RESULTS

The search identified 2028 citations, from which we selected 474 studies for detailed assessment of the full texts. Finally, 100 published studies met the eligibility criteria for qualitative and 32 for quantitative syntheses. Twenty-three studies reported on performance of placental growth factor testing for the prediction of preeclampsia in the second trimester, including 16 (with 27 entries) that reported on placental growth factor test alone, 9 (with 19 entries) that reported on the soluble fms-like tyrosine kinase-1-placental growth factor ratio, and 6 (16 entries) that reported on placental growth factor-based models. Fourteen studies reported on performance of placental growth factor testing for the prediction of preeclampsia in the third trimester, including 10 (with 18 entries) that reported on placental growth factor test alone, 8 (with 12 entries) that reported on soluble fms-like tyrosine kinase-1-placental growth factor ratio, and 7 (with 12 entries) that reported on placental growth factor-based models. For the second trimester, Placental growth factor-based models achieved the highest diagnostic odds ratio for the prediction of early preeclampsia in the total population compared with placental growth factor alone and soluble fms-like tyrosine kinase-1-placental growth factor ratio (placental growth factor-based models, 63.20; 95% confidence interval, 37.62-106.16 vs soluble fms-like tyrosine kinase-1-placental growth factor ratio, 6.96; 95% confidence interval, 1.76-27.61 vs placental growth factor alone, 5.62; 95% confidence interval, 3.04-10.38); placental growth factor-based models had higher diagnostic odds ratio than placental growth factor alone for the identification of any-onset preeclampsia in the unselected population (28.45; 95% confidence interval, 13.52-59.85 vs 7.09; 95% confidence interval, 3.74-13.41). For the third trimester, Placental growth factor-based models achieved prediction for any-onset preeclampsia that was significantly better than that of placental growth factor alone but similar to that of soluble fms-like tyrosine kinase-1-placental growth factor ratio (placental growth factor-based models, 27.12; 95% confidence interval, 21.67-33.94 vs placental growth factor alone, 10.31; 95% confidence interval, 7.41-14.35 vs soluble fms-like tyrosine kinase-1-placental growth factor ratio, 14.94; 95% confidence interval, 9.42-23.70).

CONCLUSION

Placental growth factor with maternal factors ± other biomarkers determined in the second trimester achieved the best predictive performance for early preeclampsia in the total population. However, in the third trimester, placental growth factor-based models had predictive performance for any-onset preeclampsia that was better than that of placental growth factor alone but similar to that of soluble fms-like tyrosine kinase-1-placental growth factor ratio. Through this meta-analysis, we have identified a large number of very heterogeneous studies. Therefore, there is an urgent need to develop standardized research using the same models that combine serum placental growth factor with maternal factors ± other biomarkers to accurately predict preeclampsia. Identification of patients at risk might be beneficial for intensive monitoring and timing delivery.

Evolutionary perspective of uteroplacental malperfusion: subjacent insult common to most pregnancy complications

Linked article: There is a comment on this article by Yagel et al. Click here to view the Correspondence.

Sequential disruptions to inflammatory and angiogenic pathways and risk of spontaneous preterm birth in Malawian women

Preterm birth is a leading cause of death in children under five years of age. We hypothesized that sequential disruptions to inflammatory and angiogenic pathways during pregnancy increase the risk of placental insufficiency and spontaneous preterm labor and delivery. We conducted a secondary analysis of inflammatory and angiogenic analytes measured in plasma samples collected across pregnancy from 1462 Malawian women. Women with concentrations of the inflammatory markers sTNFR2, CHI3L1, and IL18BP in the highest quartile before 24 weeks gestation and women with anti-angiogenic factors sEndoglin and sFlt-1/PlGF ratio in the highest quartile at 28-33 weeks gestation had an increased relative risk of preterm birth. Mediation analysis further supported a potential causal link between early inflammation, subsequent angiogenic dysregulation detrimental to placental vascular development, and earlier gestational age at delivery. Interventions designed to reduce the burden of preterm birth may need to be implemented before 24 weeks of gestation.

Assessment-based management of placenta-mediated pregnancy complications: Pragmatism until a precision medicine approach evolves

The management of pregnant women with thrombophilia and a history of gestational vascular complications remains debatable. Treatment of the latter is often based on clinical outcome rather than disease mechanism. While the use of venous thromboembolism prophylaxis in pregnancy is recommended for those at increased risk, the ability of anticoagulant and/or antiplatelet agents to lower the risk of placenta-mediated complications in this clinical setting remains controversial. The available guidelines are inconsistent in some situations, which reflects the limited evidence base. This review critically discusses risk assessment models (RAMs) and management strategies of women with thrombophilia and pregnancy complications, using clinical vignettes. RAMs, taking into account obstetric and thrombotic history as well as thrombophilia status, could drive a precision medicine approach, based on disease mechanism, and guide individual therapeutic interventions in high-risk clinical settings.

Perturbations in kinetics of the thrombin generation assay identify women at risk of preeclampsia in the first trimester and provide the rationale for a preventive approach

BACKGROUND

Activation of the coagulation system and increased thrombin generation have been implicated in the pathophysiology of preeclampsia, and this rationale supports the administration of low-molecular-weight heparin to prevent this syndrome in patients at risk. Yet, randomized trials of this prophylactic measure have yielded contradictory results. A possible explanation is that only a subset of patients with preeclampsia have excessive thrombin generation and would benefit from the administration of low-molecular-weight heparin. Therefore, the key questions are whether and when patients who subsequently develop preeclampsia present evidence of abnormal thrombin generation.

OBJECTIVE

This study aimed to determine (1) the kinetics of thrombin generation throughout gestation in women with a normal pregnancy and in those with early and late preeclampsia, and (2) the diagnostic performance of in vivo thrombin generation parameters to predict the development of preeclampsia.

STUDY DESIGN

This retrospective, nested case-control study was based on a prospective longitudinal cohort of singleton gestations. Cases comprised women who developed preeclampsia (n=49), and controls consisted of patients with a normal pregnancy (n=45). Preeclampsia was classified into early-onset (n=24) and late-onset (n=25). Longitudinal changes in the parameters of the thrombin generation assay (lag time, time to peak thrombin concentration, peak thrombin concentration, endogenous thrombin generation, and velocity index) throughout gestation were compared between the study groups, and normal pregnancy percentiles were derived from the control group. We tested whether a single parameter or a combination of parameters, derived from the kinetics of thrombin generation, could identify patients who subsequently developed preeclampsia. Time-related parameters <10th percentile were considered short, and concentration-related parameters >90th percentile were considered high.

RESULTS

(1) Patients who developed preeclampsia (early- and late-onset) had abnormal thrombin generation kinetics as early as 8 to 16 weeks of pregnancy; (2) patients with a combination of a short lag time and high peak thrombin concentration at 8 to 16 weeks of pregnancy had an odds ratio of 43.87 for the subsequent development of preeclampsia (area under the curve, 0.79; sensitivity, 56.8%; specificity, 92.7%; positive likelihood ratio, 7.76); (3) at 16 to 22 weeks of gestation, patients with a combination of a short lag time and a high velocity index had an odds ratio of 16 for the subsequent development of preeclampsia (area under the curve, 0.78; sensitivity, 62.2%; specificity, 92.5%; positive likelihood ratio, 8.29).

CONCLUSION

During early pregnancy, the thrombin generation assay can identify the subset of patients at a greater risk for the development of preeclampsia owing to accelerated and enhanced production of thrombin. This observation provides a rationale for testing the efficacy of low-molecular-weight heparin in this subset of patients. We propose that future research on the efficacy of low-molecular-weight heparin and other interventions targeting the coagulation system to prevent preeclampsia should be focused on patients with abnormal kinetics of thrombin generation.

Preeclampsia at term can be classified into 2 clusters with different clinical characteristics and outcomes based on angiogenic biomarkers in maternal blood

BACKGROUND

An antiangiogenic state has emerged as a mechanism of disease in preeclampsia. Angiogenic biomarkers are used in the risk assessment of this syndrome, particularly of early disease. The role of an antiangiogenic state in late preeclampsia is unclear.

OBJECTIVE

This study aimed to determine the prevalence, characteristics, and clinical significance of angiogenic/antiangiogenic factor abnormalities in women with preeclampsia stratified according to gestational age at delivery.

STUDY DESIGN

Two studies were conducted: (1) a longitudinal nested case-control study comprising women with preeclampsia (n=151) and a control group (n=540); and (2) a case series of patients with preeclampsia (n=452). In patients with preeclampsia, blood was collected at the time of diagnosis. Plasma concentrations of placental growth factor and soluble fms-like tyrosine kinase-1 were determined by enzyme-linked immunosorbent assays. An abnormal angiogenic profile was defined as a plasma ratio of placental growth factor and soluble fms-like tyrosine kinase-1 expressed as a multiple of the median <10th percentile for gestational age based on values derived from the longitudinal study. The proportion of patients diagnosed with preeclampsia who had an abnormal angiogenic profile was determined in the case-series participants and stratified by gestational age at delivery into early (≤34 weeks), intermediate (34.1-36.9 weeks), and term (≥37 weeks) preeclampsia. The demographics, clinical characteristics, and pregnancy outcomes of women with preeclampsia with and without an abnormal angiogenic profile were compared.

RESULTS

The prevalence of an abnormal angiogenic profile was higher in preterm than in term preeclampsia (for early, intermediate, and term in the case-control study: 90%, 100%, and 39%; for the case series: 98%, 80%, and 55%, respectively). Women with preeclampsia at term who had an abnormal angiogenic profile were more frequently nulliparous (57% vs 35%), less likely to smoke (14% vs 26%), at greater risk for maternal (14% vs 5%) or neonatal (7% vs 1%) complications, and more often had placental lesions consistent with maternal vascular malperfusion (42% vs 23%; all, P<.05) than those without an abnormal profile. Women with preeclampsia at term who had a normal angiogenic profile had a higher frequency of chronic hypertension (36% vs 21%) and were more likely to have class ≥2 obesity (41% vs 23%) than those with an abnormal profile (both, P<.05).

CONCLUSION

Patients with early preeclampsia had an abnormal angiogenic profile in virtually all cases, whereas only 50% of women with preeclampsia at term had such abnormalities. The profile of angiogenic biomarkers can be used to classify patients with preeclampsia at term, on the basis of mechanisms of disease, into 2 clusters, which have different demographics, clinical characteristics, and risks of adverse maternal and neonatal outcomes. These findings provide a simple approach to classify preeclampsia at term and have implications for future clinical care and research.

Human Plasma Proteome During Normal Pregnancy

The human plasma proteome is underexplored despite its potential value for monitoring health and disease. Herein, using a recently developed aptamer-based platform, we profiled 7288 proteins in 528 plasma samples from 91 normal pregnancies (Gene Expression Omnibus identifier GSE206454). The coefficient of variation was <20% for 93% of analytes (median 7%), and a cross-platform correlation for selected key angiogenic and anti-angiogenic proteins was significant. Gestational age was associated with changes in 953 proteins, including highly modulated placenta- and decidua-specific proteins, and they were enriched in biological processes including regulation of growth, angiogenesis, immunity, and inflammation. The abundance of proteins corresponding to RNAs specific to populations of cells previously described by single-cell RNA-Seq analysis of the placenta was highly modulated throughout gestation. Furthermore, machine learning-based prediction of gestational age and of time from sampling to term delivery compared favorably with transcriptomic models (mean absolute error of 2 weeks). These results suggested that the plasma proteome may provide a non-invasive readout of placental cellular dynamics and serve as a blueprint for investigating obstetrical disease.

Cumulative effect of maternal vascular malperfusion types in the placenta on adverse pregnancy outcomes

INTRODUCTION

Placental vascular disease, characterized by Maternal Vascular Malperfusion (MVM) lesions, is considered to be the underlying cause of pregnancy complications. Aim is to evaluate the relationship between the cumulative number of MVM lesion types, and adverse pregnancy- and neonatal outcomes.

METHODS

This retrospective cohort study included 272 women with singleton gestations who gave birth at a Dutch tertiary hospital between 2017 and 2018 with available placental histopathology reports. Analyzed according to the Amsterdam Placental Workshop Group Consensus Statement, placentas were divided into groups based on the cumulative number of MVM lesions: no lesions (n = 124), 1-2 types (n = 124) and 3-5 types of lesions (n = 24).

RESULTS

The proportion of placenta syndrome (PS) was highest (95.8%) in the 3-5 MVM lesions group (p < 0.001). The presence of MVM lesions was highly associated with PS during pregnancy (aOR 6.81, 95% CI 3.76-12.33). Furthermore, every additional type of MVM lesion corresponded with a threefold increased odds for the occurrence of PS (aOR 3.00, 95% CI 2.10-4.29). The group with 3-5 types of MVM lesions showed the highest incidence of adverse neonatal outcomes, lower mean birth weight, prolonged hospitalization, NICU admissions and neonatal deaths (aOR 6.47, 95% CI 0.33-127.68), corresponding with a fourfold increased odds for the occurrence of neonatal death for every additional MVM lesion (aOR 4.19, 95% CI 1.39-12.68).

DISCUSSION

A higher number of MVM lesion types is strongly associated with an increased incidence of adverse pregnancy- and neonatal outcomes, indicating that guidelines should focus also on the amount of MVM lesion types for the monitoring/management of subsequent pregnancies.

Preeclampsia and Fetal Growth Restriction as Risk Factors of Future Maternal Cardiovascular Disease-A Review

Cardiovascular diseases (CVDs) remain the leading cause of death in women worldwide. Although traditional risk factors increase later-life CVD, pregnancy-associated complications additionally influence future CVD risk in women. Adverse pregnancy outcomes, including preeclampsia and fetal growth restriction (FGR), are interrelated disorders caused by placental dysfunction, maternal cardiovascular maladaptation to pregnancy, and maternal abnormalities such as endothelial dysfunction, inflammation, hypercoagulability, and vasospasm. The pathophysiologic pathways of some pregnancy complications and CVDs might be linked. This review aimed to highlight the associations between specific adverse pregnancy outcomes and future CVD and emphasize the importance of considering pregnancy history in assessing a woman's CVD risk. Moreover, we wanted to underline the role of maternal cardiovascular maladaptation in the development of specific pregnancy complications such as FGR.

Toward a new taxonomy of obstetrical disease: improved performance of maternal blood biomarkers for the great obstetrical syndromes when classified according to placental pathology

BACKGROUND

The major challenge for obstetrics is the prediction and prevention of the great obstetrical syndromes. We propose that defining obstetrical diseases by the combination of clinical presentation and disease mechanisms as inferred by placental pathology will aid in the discovery of biomarkers and add specificity to those already known.

OBJECTIVE

To describe the longitudinal profile of placental growth factor (PlGF), soluble fms-like tyrosine kinase-1 (sFlt-1), and the PlGF/sFlt-1 ratio throughout gestation, and to determine whether the association between abnormal biomarker profiles and obstetrical syndromes is strengthened by information derived from placental examination, eg, the presence or absence of placental lesions of maternal vascular malperfusion.

STUDY DESIGN

This retrospective case cohort study was based on a parent cohort of 4006 pregnant women enrolled prospectively. The case cohort of 1499 pregnant women included 1000 randomly selected patients from the parent cohort and all additional patients with obstetrical syndromes from the parent cohort. Pregnant women were classified into six groups: 1) term delivery without pregnancy complications (n=540; control); 2) preterm labor and delivery (n=203); 3) preterm premature rupture of the membranes (n=112); 4) preeclampsia (n=230); 5) small-for-gestational-age neonate (n=334); and 6) other pregnancy complications (n=182). Maternal plasma concentrations of PlGF and sFlt-1 were determined by enzyme-linked immunosorbent assays in 7560 longitudinal samples. Placental pathologists, masked to clinical outcomes, diagnosed the presence or absence of placental lesions of maternal vascular malperfusion. Comparisons between mean biomarker concentrations in cases and controls were performed by utilizing longitudinal generalized additive models. Comparisons were made between controls and each obstetrical syndrome with and without subclassifying cases according to the presence or absence of placental lesions of maternal vascular malperfusion.

RESULTS

1) When obstetrical syndromes are classified based on the presence or absence of placental lesions of maternal vascular malperfusion, significant differences in the mean plasma concentrations of PlGF, sFlt-1, and the PlGF/sFlt-1 ratio between cases and controls emerge earlier in gestation; 2) the strength of association between an abnormal PlGF/sFlt-1 ratio and the occurrence of obstetrical syndromes increases when placental lesions of maternal vascular malperfusion are present (adjusted odds ratio [aOR], 13.6 vs 6.7 for preeclampsia; aOR, 8.1 vs 4.4 for small-for-gestational-age neonates; aOR, 5.5 vs 2.1 for preterm premature rupture of the membranes; and aOR, 3.3 vs 2.1 for preterm labor (all P<0.05); and 3) the PlGF/sFlt-1 ratio at 28 to 32 weeks of gestation is abnormal in patients who subsequently delivered due to preterm labor with intact membranes and in those with preterm premature rupture of the membranes if both groups have placental lesions of maternal vascular malperfusion. Such association is not significant in patients with these obstetrical syndromes who do not have placental lesions.

CONCLUSION

Classification of obstetrical syndromes according to the presence or absence of placental lesions of maternal vascular malperfusion allows biomarkers to be informative earlier in gestation and enhances the strength of association between biomarkers and clinical outcomes. We propose that a new taxonomy of obstetrical disorders informed by placental pathology will facilitate the discovery and implementation of biomarkers as well as the prediction and prevention of such disorders.

Placental protein levels in maternal serum are associated with adverse pregnancy outcomes in nulliparous patients

BACKGROUND

The Eunice Kennedy Shriver National Institute of Child Health and Human Development Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be was established to investigate the underlying causes and pathophysiological pathways associated with adverse pregnancy outcomes in nulliparous gravidas.

OBJECTIVE

This study aimed to study placental physiology and identify novel biomarkers concerning adverse pregnancy outcomes, including preterm birth (medically indicated and spontaneous), preeclampsia, small-for-gestational-age neonates, and stillbirth. We measured levels of placental proteins in the maternal circulation in the first 2 trimesters of pregnancy.

STUDY DESIGN

Maternal serum samples were collected at 2 study visits (6-13 weeks and 16-21 weeks), and levels of 9 analytes were measured. The analytes we measured were vascular endothelial growth factor, placental growth factor, endoglin, soluble fms-like tyrosine kinase-1, A disintegrin and metalloproteinase domain-containing protein 12, pregnancy-associated plasma protein A, free beta-human chorionic gonadotropin, inhibin A, and alpha-fetoprotein. The primary outcome was preterm birth between 20 0/7 and 36 6/7 weeks of gestation. The secondary outcomes were spontaneous preterm births, medically indicated preterm births, preeclampsia, small-for-gestational-age neonates, and stillbirth.

RESULTS

A total of 10,038 eligible gravidas were enrolled in the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be cohort, from which a nested case-control study was performed comparing 800 cases with preterm birth (466 spontaneous preterm births, 330 medically indicated preterm births, and 4 unclassified preterm births), 568 with preeclampsia, 406 with small-for-gestational-age birth, and 49 with stillbirth with 911 controls who delivered at term without complications. Although levels of each analyte generally differed between cases and controls at 1 or 2 visits, the odds ratios revealed a <2-fold difference between cases and controls in all comparisons. Receiver operating characteristic curves, generated to determine the relationship between analyte levels and preterm birth and the other adverse pregnancy outcomes, resulted in areas under the receiver operating characteristic curves that were relatively low (range, 0.50-0.64) for each analyte. Logistic regression modeling demonstrated that areas under the receiver operating characteristic curves for predicting adverse pregnancy outcomes were greater using baseline clinical characteristics and combinations of analytes than baseline characteristics alone, but areas under the receiver operating characteristic curves remained relatively low for each outcome (range, 0.65-0.78).

CONCLUSION

We have found significant associations between maternal serum levels of analytes evaluated early in pregnancy and subsequent adverse pregnancy outcomes in nulliparous gravidas. However, the test characteristics for these analytes do not support their use as clinical biomarkers to predict adverse pregnancy outcomes, either alone or in combination with maternal clinical characteristics.

The Global Pregnancy Collaboration (CoLab) symposium on short- and long-term outcomes in offspring whose mothers had preeclampsia: A scoping review of clinical evidence

Preeclampsia is a maternal syndrome characterized by the new onset of hypertension after 20 weeks of gestation associated with multisystemic complications leading to high maternal and fetal/neonatal morbidity and mortality. However, sequelae of preeclampsia may extend years after pregnancy in both mothers and their children. In addition to the long-term adverse cardiovascular effects of preeclampsia in the mother, observational studies have reported elevated risk of cardiovascular, metabolic, cerebral and cognitive complications in children born from women with preeclampsia. Less clear is whether the association between maternal preeclampsia and offspring sequelae are causal, or to what degree the associations might be driven by fetal factors including impaired growth and the health of its placenta. Our discussion of these complexities in the 2018 Global Pregnancy Collaboration annual meeting prompted us to write this review. We aimed to summarize the evidence of an association between maternal preeclampsia and neurobehavioral developmental disorders in offspring in hopes of generating greater research interest in this important topic.

Severe maternal infectious morbidity during the second half of pregnancy is an independent risk factor for a small for gestational age neonate

OBJECTIVE

The effect of severe maternal infectious morbidity on fetal growth during the second half of pregnancy is under debate. Preliminary evidence suggests that such association may be plausible. The objectives of this study were to determine: 1) The association between severe maternal infectious morbidity and adverse pregnancy outcome; and 2) The effect of maternal infection during pregnancy on fetal growth.

STUDY DESIGN

This retrospective population - based cohort study included 4771 women who gave birth at our medical center during the study period. Parturients were allocated into two groups: 1) patients with severe maternal infection during the second half of pregnancy (n = 368); and 2) control group comprised of normal pregnant women who were matched to the study group by maternal age, gravidity and parity (n = 4403).

RESULTS

The severe maternal infection group included women with pneumonia (n = 198), pyelonephritis (n = 131), and viral pneumonitis (n = 39). In comparison to the normal patients group: 1) having had pneumonia during the second half of pregnancy was associated with increased rates of fetal growth restriction, placental abruption, fetal demise (P < 0.001, for all comparisons) and preeclampsia (P = 0.041); 2) Pyelonephritis during the second half of gestation was associated with higher rates of fetal growth restriction (P < 0.001), placental abruption (P = 0.006) and labor induction (P = 0.039). As a group, women with severe maternal infection had higher rates of small for gestational age neonates compared to normal parturients (P < 0.001). Among women with infections, only those who had pyelonephritis (P = 0.032) or pneumonia (P = 0.008), had a higher rate of small for gestational age neonates than those in the control group. After adjustment to confounding factors, maternal infection (OR = 1.42, 95% CI 1.085-1.85) and previous delivery of a small for gestational age neonate (OR = 2.54, 95% CI 2.02-3.19), were independent risk factors for the delivery of a small for gestational age neonate.

CONCLUSION

Severe maternal infectious morbidity during the second half of pregnancy is an independent risk factor for the delivery of a small for gestational age neonate and is associated with adverse pregnancy outcomes. Both, pneumonia and pyelonephritis, during the second half of gestation affect fetal growth and are related to higher rates of small for gestational age neonates.

The role of the placenta in spontaneous preterm labor and delivery with intact membranes

OBJECTIVES

To determine whether placental vascular pathology and impaired placental exchange due to maturational defects are involved in the etiology of spontaneous preterm labor and delivery in cases without histologic acute chorioamnionitis.

METHODS

This was a retrospective, observational study. Cases included pregnancies that resulted in spontaneous preterm labor and delivery (<37 weeks), whereas uncomplicated pregnancies that delivered fetuses at term (≥37-42 weeks of gestation) were selected as controls. Placental histological diagnoses were classified into three groups: lesions of maternal vascular malperfusion, lesions of fetal vascular malperfusion, and placental microvasculopathy, and the frequency of each type of lesion in cases and controls was compared. Moreover, we specifically searched for villous maturational abnormalities in cases and controls. Doppler velocimetry of the umbilical and uterine arteries were performed in a subset of patients.

RESULTS

There were 184 cases and 2471 controls, of which 95 and 1178 had Doppler studies, respectively. The frequency of lesions of maternal vascular malperfusion was greater in the placentas of patients with preterm labor than in the control group [14.1% (26/184) vs. 8.8% (217/2471) (p=0.023)]. Disorders of villous maturation were more frequent in the group with preterm labor than in the control group: 41.1% (39/95) [delayed villous maturation in 31.6% (30/95) vs. 2.5% (13/519) in controls and accelerated villous maturation in 9.5% (9/95) vs. none in controls].

CONCLUSIONS

Maturational defects of placental villi were associated with approximately 41% of cases of unexplained spontaneous preterm labor and delivery without acute inflammatory lesions of the placenta and with delivery of appropriate-for-gestational-age fetuses.

Evaluation of placental oxygenation in fetal growth restriction using blood oxygen level-dependent magnetic resonance imaging

INTRODUCTION

Abnormalities in placental function can lead to fetal growth restriction (FGR), but there is no consensus on their evaluation. Using blood oxygen level-dependent magnetic resonance imaging (BOLD MRI), we compared placental oxygenation between FGR cases and previously reported normal pregnancies.

METHODS

Eight singleton pregnant women (>32 weeks of gestation) diagnosed with fetal growth failure during pregnancy were recruited. BOLD MRI was consecutively performed under normoxia (21% O₂), hyperoxia (100% O₂), and normoxia for 4 min each. Each placental time-activity curve was evaluated to calculate the peak score (peakΔR2*) and the time from the start of maternal oxygen administration to the time of peakΔR2* (time to peakΔR2*). In six of the eight FGR cases, placental FGR-related pathological findings were evaluated after delivery.

RESULTS

The parameter peakΔR2* was significantly decreased in the FGR group (8 ± 3 vs 6 ± 1, p < 0.001), but there was no significant difference in time to peakΔR2* (458 ± 74 s vs 468 ± 57 s, p = 0.750). The findings in the six FGR cases assessed for placental pathologies included chorangiosis in two cases, avascular chorions in two cases, placental infarction in two cases, and syncytial knot formation in one case.

DISCUSSION

The peakΔR2* values were lower in the FGR group than in the normal pregnancy group. This suggests that oxygenation of the placenta is decreased in the FGR group compared to the normal group, and this may be related to FGR. Placental pathology also revealed findings possibly related to FGR, suggesting that low peakΔR2* values in the FGR group may reflect placental dysfunction.

Diagnostic utility of serial circulating placental growth factor levels and uterine artery Doppler waveforms in diagnosing underlying placental diseases in pregnancies at high risk of placental dysfunction

BACKGROUND

Placental pathology assessment following delivery in pregnancies complicated by preeclampsia, fetal growth restriction, abruption, and stillbirth reveals a range of underlying diseases. The most common pathology is maternal vascular malperfusion, characterized by high-resistance uterine artery Doppler waveforms and abnormal expression of circulating maternal angiogenic growth factors. Rare placental diseases (massive perivillous fibrinoid deposition and chronic histiocytic intervillositis) are reported to have high recurrence risks, but their associations with uterine artery Doppler waveforms and angiogenic growth factors are presently ill-defined.

OBJECTIVE

To characterize the patterns of serial placental growth factor measurements and uterine artery Doppler waveform assessments in pregnancies that develop specific types of placental pathology to gain insight into their relationships with the timing of disease onset and pregnancy outcomes.

STUDY DESIGN

A retrospective cohort study conducted between January 2017 and November 2021 included all singleton pregnancies with at least 1 measurement of maternal circulating placental growth factor between 16 and 36 weeks' gestation, delivery at our institution, and placental pathology analysis demonstrating diagnostic features of maternal vascular malperfusion, fetal vascular malperfusion, villitis of unknown etiology, chronic histiocytic intervillositis, or massive perivillous fibrinoid deposition. Profiles of circulating placental growth factor as gestational age advanced were compared between these placental pathologies. Maternal and perinatal outcomes were recorded.

RESULTS

A total of 337 pregnancies from 329 individuals met our inclusion criteria. These comprised placental pathology diagnoses of maternal vascular malperfusion (n=109), fetal vascular malperfusion (n=87), villitis of unknown etiology (n=96), chronic histiocytic intervillositis (n=16), and massive perivillous fibrinoid deposition (n=29). Among patients who developed maternal vascular malperfusion, placental growth factor levels gradually declined as pregnancy progressed (placental growth factor <10th percentile at 16-20 weeks' gestation in 42.9%; 20-24 weeks in 61.9%; 24-28 weeks in 77%; and 28-32 weeks in 81.4%) accompanied by mean uterine artery Doppler pulsatility index >95th percentile in 71.6% cases. Patients who developed either fetal vascular malperfusion or villitis of unknown etiology mostly exhibited normal circulating placental growth factor values in association with normal uterine artery Doppler waveforms (mean [standard deviation] pulsatility index values: fetal vascular malperfusion, 1.14 [0.49]; villitis of unknown etiology, 1.13 [0.45]). Patients who developed either chronic histiocytic intervillositis or massive perivillous fibrinoid deposition exhibited persistently low placental growth factor levels from the early second trimester (placental growth factor <10th centile at 16-20 weeks' gestation in 80% and 77.8%, respectively; 20-24 weeks in 88.9% and 63.6%; 24-28 weeks in 85.7% and 75%), all in combination with normal uterine artery Doppler waveforms (mean pulsatility index >95th centile: chronic histiocytic intervillositis, 25%; massive perivillous fibrinoid deposition, 37.9%). Preeclampsia developed in 83 of 337 (24.6%) patients and was most common in those developing maternal vascular malperfusion (54/109, 49.5%) followed by chronic histiocytic intervillositis (7/16, 43.8%). There were 29 stillbirths in the cohort (maternal vascular malperfusion, n=10 [9.2%]; fetal vascular malperfusion, n=5 [5.7%]; villitis of unknown etiology, n=1 [1.0%]; chronic histiocytic intervillositis, n=7 [43.8%]; massive perivillous fibrinoid deposition, n=6 [20.7%]). Most patients experiencing stillbirth exhibited normal uterine artery Doppler waveforms (21/29, 72.4%) and had nonmaternal vascular malperfusion pathologies (19/29, 65.5%). By contrast, 28 of 29 (96.5%) patients experiencing stillbirth had ≥1 low placental growth factor values before fetal death.

CONCLUSION

Serial circulating maternal placental growth factor tests, in combination with uterine artery Doppler waveform assessments in the second trimester, may indicate the likely underlying type of placental pathology mediating severe adverse perinatal events. This approach has the potential to test disease-specific therapeutic strategies to improve clinical outcomes. Serial placental growth factor testing, compared with uterine artery Doppler studies, identifies a greater proportion of patients destined to have a poor perinatal outcome because diseases other than maternal vascular malperfusion are characterized by normal uteroplacental circulation.

Circulating maternal placental growth factor responses to low-molecular-weight heparin in pregnant patients at risk of placental dysfunction

BACKGROUND

Patients at high risk of severe preeclampsia and fetal growth restriction have low circulating levels of placental growth factor and features of maternal vascular malperfusion placental pathology at delivery. Multimodal screening and commencement of aspirin prophylaxis at 11 to 13 weeks' gestation markedly reduces the risk of preterm delivery with preeclampsia. However, the additional role of low-molecular-weight heparin and mechanisms of action remain uncertain. Because low-molecular-weight heparin augments the production and release of placental growth factor in vitro by both placental villi and vascular endothelium, it may be effective to suppress the risk of severe preeclampsia in a niche group of high-risk patients with low circulating placental growth factor in the early second trimester.

OBJECTIVE

This study aimed to define a gestational age-specific reference range for placental growth factor and to test the hypothesis that prophylactic low-molecular-weight heparin administered in the early second trimester may restore deficient circulating placental growth factor levels and thereby prolong pregnancy.

STUDY DESIGN

Centile curves for circulating placental growth factor levels from 12 to 36 weeks' gestation were derived using quantile regression of combined data from a published cohort of 4207 unselected nulliparous patients in Cambridge, United Kingdom, at 4 sampling time points (12, 20, 28, and 36 weeks' gestation) and the White majority (n=531) of a healthy nulliparous cohort in Toronto, Canada, at 16 weeks' gestation using the same test platform. Within a specialty high-risk clinic in Toronto, a niche group of 7 patients with a circulating placental growth factor at the <10th centile in the early second trimester received daily prophylactic low-molecular-weight heparin (enoxaparin; 40 mg subcutaneously) and were followed up until delivery (group 1). Their baseline characteristics, delivery details, and placental pathologies were compared with 5 similar patients who did not receive low-molecular-weight heparin during the observation period (group 2) and further with 21 patients who delivered with severe preeclampsia (group 3) in the same institution.

RESULTS

A gestational age-specific reference range for placental growth factor levels at weekly intervals between 12 and 36 weeks was established for White women with singleton pregnancies. Within group 1, 5 of 7 patients demonstrated a sustained increase in circulating placental growth factor levels, whereas placental growth factor levels did not increase in group 2 or group 3 patients who did not receive low-molecular-weight heparin. Group 1 patients receiving low-molecular-weight heparin therapy exhibited a later gestation at delivery, relative to groups 2 and 3 (36 weeks [33-37] vs 23 weeks [22-26] and 28 weeks [27-31], respectively), and consequently had higher birthweights (1.93 kg [1.1-2.7] vs 0.32 kg [0.19-0.39] and 0.73 kg [0.52-1.03], respectively). The incidence of stillbirth was lowest in group 1 (14% [1 of 7]), relative to groups 2 and 3 (80% [4 of 5] and 29% [6 of 21], respectively). Maternal vascular malperfusion was the most common placental pathology found in association with abnormal uterine artery Doppler.

CONCLUSION

In patients at high risk of a serious adverse pregnancy outcome owing to placental disease, the addition of low-molecular-weight heparin to aspirin prophylaxis in the early second trimester may restore deficient circulating placental growth factor to mediate an improved perinatal outcome. These data support the implementation of a multicenter pilot randomized control trial where patients are recruited primarily based on the assessment of placental function in the early second trimester.

Prediction of preeclampsia throughout gestation with maternal characteristics and biophysical and biochemical markers: a longitudinal study

BACKGROUND

The current approach to predict preeclampsia combines maternal risk factors and evidence from biophysical markers (mean arterial pressure, Doppler velocimetry of the uterine arteries) and maternal blood proteins (placental growth factor, soluble vascular endothelial growth factor receptor-1, pregnancy-associated plasma protein A). Such models require the transformation of biomarker data into multiples of the mean values by using population- and site-specific models. Previous studies have focused on a narrow window in gestation and have not included the maternal blood concentration of soluble endoglin, an important antiangiogenic factor up-regulated in preeclampsia.

OBJECTIVE

This study aimed (1) to develop models for the calculation of multiples of the mean values for mean arterial pressure and biochemical markers; (2) to build and assess the predictive models for preeclampsia based on maternal risk factors, the biophysical (mean arterial pressure) and biochemical (placental growth factor, soluble vascular endothelial growth factor receptor-1, and soluble endoglin) markers collected throughout pregnancy; and (3) to evaluate how prediction accuracy is affected by the presence of chronic hypertension and gestational age.

STUDY DESIGN

This longitudinal case-cohort study included 1150 pregnant women: women without preeclampsia with (n=49) and without chronic hypertension (n=871) and those who developed preeclampsia (n=166) or superimposed preeclampsia (n=64). Mean arterial pressure and immunoassay-based maternal plasma placental growth factor, soluble vascular endothelial growth factor receptor-1, and soluble endoglin concentrations were available throughout pregnancy (median of 5 observations per patient). A prior-risk model for preeclampsia was established by using Poisson regression based on maternal characteristics and obstetrical history. Next, multiple regression was used to fit biophysical and biochemical marker data as a function of maternal characteristics by using data collected at 8 to 15⁺⁶, 16 to 19⁺⁶, 20 to 23⁺⁶, 24 to 27⁺⁶, 28 to 31⁺⁶, and 32 to 36⁺⁶ week intervals, and observed values were converted into multiples of the mean values. Then, multivariable prediction models for preeclampsia were fit based on the biomarker multiples of the mean data and prior-risk estimates. Separate models were derived for overall, preterm, and term preeclampsia, which were evaluated by receiver operating characteristic curves and sensitivity at fixed false-positive rates.

RESULTS

(1) The inclusion of soluble endoglin in prediction models for all preeclampsia, together with the prior-risk estimates, mean arterial pressure, placental growth factor, and soluble vascular endothelial growth factor receptor-1, increased the sensitivity (at a fixed false-positive rate of 10%) for early prediction of superimposed preeclampsia, with the largest increase (from 44% to 54%) noted at 20 to 23⁺⁶ weeks (McNemar test, P<.05); (2) combined evidence from prior-risk estimates and biomarkers predicted preterm preeclampsia with a sensitivity (false-positive rate, 10%) of 55%, 48%, 62%, 72%, and 84% at 8 to 15⁺⁶, 16 to 19⁺⁶, 20 to 23⁺⁶, 24 to 27⁺⁶, and 28 to 31⁺⁶ week intervals, respectively; (3) the sensitivity for term preeclampsia (false-positive rate, 10%) was 36%, 36%, 41%, 43%, 39%, and 51% at 8 to 15⁺⁶, 16 to 19⁺⁶, 20 to 23⁺⁶, 24 to 27⁺⁶, 28 to 31⁺⁶, and 32 to 36⁺⁶ week intervals, respectively; (4) the detection rate for superimposed preeclampsia among women with chronic hypertension was similar to that in women without chronic hypertension, especially earlier in pregnancy, reaching at most 54% at 20 to 23⁺⁶ weeks (false-positive rate, 10%); and (5) prediction models performed comparably to the Fetal Medicine Foundation calculators when the same maternal risk factors and biomarkers (mean arterial pressure, placental growth factor, and soluble vascular endothelial growth factor receptor-1 multiples of the mean values) were used as input.

CONCLUSION

We introduced prediction models for preeclampsia throughout pregnancy. These models can be useful to identify women at risk during the first trimester who could benefit from aspirin treatment or later in pregnancy to inform patient management. Relative to prediction performance at 8 to 15⁺⁶ weeks, there was a substantial improvement in the detection rate for preterm and term preeclampsia by using data collected after 20 and 32 weeks' gestation, respectively. The inclusion of plasma soluble endoglin improves the early prediction of superimposed preeclampsia, which may be valuable when Doppler velocimetry of the uterine arteries is not available.

Endothelial dysfunction in preterm infants: The hidden legacy of uteroplacental pathologies

Millions of infants are born prematurely every year worldwide. Prematurity, particularly at lower gestational ages, is associated with high mortality and morbidity and is a significant global health burden. Pregnancy complications and preterm birth syndrome strongly impact neonatal clinical phenotypes and outcomes. The vascular endothelium is a pivotal regulator of fetal growth and development. In recent years, the key role of uteroplacental pathologies impairing endothelial homeostasis is emerging. Conditions leading to very and extremely preterm birth can be classified into two main pathophysiological patterns or endotypes: infection/inflammation and dysfunctional placentation. The first is frequently related to chorioamnionitis, whereas the second is commonly associated with hypertensive disorders of pregnancy and fetal growth restriction. The nature, timing, and extent of prenatal noxa may alter fetal and neonatal endothelial phenotype and functions. Changes in the luminal surface, oxidative stress, growth factors imbalance, and dysregulation of permeability and vascular tone are the leading causes of endothelial dysfunction in preterm infants. However, the available evidence regarding endothelial physiology and damage is limited in neonates compared to adults. Herein, we discuss the current knowledge on endothelial dysfunction in the infectious/inflammatory and dysfunctional placentation endotypes of prematurity, summarizing their molecular features, available biomarkers, and clinical impact. Furthermore, knowledge gaps, shadows, and future research perspectives are highlighted.

Acute Atherosis Lesions at the Fetal-Maternal Border: Current Knowledge and Implications for Maternal Cardiovascular Health

Decidua basalis, the endometrium of pregnancy, is an important interface between maternal and fetal tissues, made up of both maternal and fetal cells. Acute atherosis is a uteroplacental spiral artery lesion. These patchy arterial wall lesions containing foam cells are predominantly found in the decidua basalis, at the tips of the maternal arteries, where they feed into the placental intervillous space. Acute atherosis is prevalent in preeclampsia and other obstetric syndromes such as fetal growth restriction. Causal factors and effects of acute atherosis remain uncertain. This is in part because decidua basalis is challenging to sample systematically and in large amounts following delivery. We summarize our decidua basalis vacuum suction method, which facilitates tissue-based studies of acute atherosis. We also describe our evidence-based research definition of acute atherosis. Here, we comprehensively review the existing literature on acute atherosis, its underlying mechanisms and possible short- and long-term effects. We propose that multiple pathways leading to decidual vascular inflammation may promote acute atherosis formation, with or without poor spiral artery remodeling and/or preeclampsia. These include maternal alloreactivity, ischemia-reperfusion injury, preexisting systemic inflammation, and microbial infection. The concept of acute atherosis as an inflammatory lesion is not novel. The lesions themselves have an inflammatory phenotype and resemble other arterial lesions of more extensively studied etiology. We discuss findings of concurrently dysregulated proteins involved in immune regulation and cardiovascular function in women with acute atherosis. We also propose a novel hypothesis linking cellular fetal microchimerism, which is prevalent in women with preeclampsia, with acute atherosis in pregnancy and future cardiovascular and neurovascular disease. Finally, women with a history of preeclampsia have an increased risk of premature cardiovascular disease. We review whether presence of acute atherosis may identify women at especially high risk for premature cardiovascular disease.

Maternal and fetal vascular lesions of malperfusion in the placentas associated with fetal and neonatal death: results of a prospective observational study

BACKGROUND

Fetal death is one of the major adverse pregnancy outcomes and is common in low- and middle-income countries. Placental lesions may play an important role in the etiology of fetal and neonatal deaths. Previous research relating placental lesions to fetal death causation was hindered by a lack of agreement on a placental classification scheme. The Amsterdam consensus statement that was published in 2016 focused its attention on malperfusions in the maternal and fetal placental circulations.

OBJECTIVE

This study aimed to investigate the relationships of placental maternal and fetal vascular malperfusions in fetal and neonatal deaths, focusing on the most important maternal clinical conditions in the pathway to fetal and neonatal deaths, such as maternal hypertension, antepartum hemorrhage, and decreased fetal growth.

STUDY DESIGN

This was a prospective, observational cohort study conducted at 2 Asian sites. The data collected included clinical history, gross and histologic evaluations of the placenta, and several other investigations and were used to determine the cause of death. The placenta was evaluated at both sites using the Amsterdam consensus framework. We estimated the risk of placental maternal and fetal vascular malperfusions in fetal and neonatal deaths.

RESULTS

Between July 2018 and January 2020 in India and Pakistan, 1633 women with placentas available for the study provided consent. Of these women, 814 had fetal deaths, 618 had preterm live births and subsequent neonatal deaths, and 201 had term live births. The prevalence of maternal vascular malperfusion was higher in the placentas associated with fetal deaths (58.4%) and preterm neonatal deaths (31.1%) than in the placentas associated with term live births (15.4%). Adjusting for site, maternal vascular malperfusion had a relative risk of 3.88 (95% confidence interval, 2.70-5.59) in fetal deaths vs term live births and a relative risk of 2.07 (95% confidence interval, 1.41-3.02) in preterm neonatal deaths vs term live births. Infarcts and distal villous hypoplasia were the most common histologic components of maternal vascular malperfusion. Compared with maternal vascular malperfusion (58.4%), fetal vascular malperfusion was less common in the placentas associated with fetal deaths (19.0%). However, there were higher frequencies of fetal vascular malperfusion in the placentas associated with fetal deaths (19.0%) than in placentas associated with neonatal deaths (8.3%) or term live birth (5.0%). Adjusting for site, fetal vascular malperfusion had a relative risk of 4.09 (95% confidence interval, 2.15-7.75) in fetal deaths vs term live births and a relative risk of 1.77 (95% confidence interval, 0.90-3.49) in preterm neonatal deaths vs term live births. Furthermore, there was a higher incidence of maternal vascular malperfusion in cases of maternal hypertension (71.4%), small for gestational age (69.9%), and antepartum hemorrhage (59.1%) than in cases of fetal deaths with none of these conditions (43.3%). There was no significant difference in the occurrence of fetal vascular malperfusion in the 4 clinical categories.

CONCLUSION

Histologic examination of the placenta, especially for malperfusion disorders, is crucial in elucidating pathways to fetal and neonatal deaths in preterm infants. In particular, focusing on placental maternal and fetal vascular malperfusions during pregnancy is a means to identify fetuses at risk of fetal death and is an important strategy to reduce the risk of fetal death early delivery. We hope that the increased risk of fetal and neonatal deaths in these pregnancies can be reduced by the development of an intervention that reduces the likelihood of developing maternal and fetal vascular malperfusion.

Association between proteinuria and placental pathology in preeclampsia: A retrospective study

Introduction:

Preeclampsia develops due to placental insufficiency and systemic proinflammatory and antiangiogenic mediator release, with ensuing systemic endothelial dysfunction. Nephrotic-range proteinuria appears to be associated with worse pregnancy outcomes. The relationship between differing degrees of proteinuria and the severity of placental alterations has not been studied.

Methods:

This is a single-centre retrospective comparison of 150 singleton pregnancies complicated by preeclampsia and varying degrees of proteinuria. Maternal demographic, obstetrical and fetal outcome data were obtained from chart review. The placental histologic evaluations were performed by a placental pathologist blinded to all other clinical information.

Results:

Preeclamptic women with massive proteinuria had evidence of more severe maternal vascular malperfusion lesions. The severity of the lesions was progressive through mild, moderate and massive proteinuria. Women with massive proteinuria had a higher incidence of renal dysfunction and severe hypertension, and had earlier preterm deliveries compared to preeclamptic women with mild and moderate proteinuria (p < 0.05).

Conclusion:

Preeclampsia with more severe proteinuria is associated with a higher prevalence of placental maternal vascular malperfusion.

The use of functional placental magnetic resonance imaging for assessment of the placenta after prolonged preterm rupture of the membranes in vivo: A pilot study

INTRODUCTION

Preterm prelabor rupture of membranes (PPROM) complicates 3% of pregnancies in the UK. Where delivery does not occur spontaneously, expectant management until 37 weeks of gestation is advocated, unless signs of maternal infection develop. However, clinical presentation of maternal infection can be a late sign and injurious fetal inflammatory responses may already have been activated. There is therefore a need for more sensitive markers to aid optimal timing of interventions. At present there is no non-invasive test in clinical practice to assess for infection in the fetal compartment and definitive diagnosis of chorioamnionitis is by histological assessment of the placenta after delivery. This study presents comprehensive functional placental magnetic resonance imaging (MRI) quantification, already used in other organ systems, to assess for infection/inflammation, in women with and without PPROM aiming to explore its use as a biomarker for inflammation within the feto-placental compartment in vivo.

MATERIAL AND METHODS

Placental MRI scans were performed in a cohort of 12 women (with one having two scans) with PPROM before 34 weeks of gestation (selected because of their high risk of infection), and in a control group of 87 women. Functional placental assessment was performed with magnetic resonance techniques sensitive to changes in the microstructure (diffusion) and tissue composition (relaxometry), with quantification performed both over the entire organ and in regions of interest between the basal and chorionic plate. Placental histology was analyzed after delivery where available.

RESULTS

Normative evolution of functional magnetic resonance biomarkers over gestation was studied. Cases of inflammation, as assessed by histological presence of chorioamnionitis, and umbilical cord vasculitis with or without funisitis, were associated with lower T2* (mean T2* at 30 weeks 50 ms compared with 58 ms in controls) and higher fractional anisotropy (mean at 30 weeks 0.55 compared with 0.45 in controls). These differences did not reach significance and there was substantial heterogeneity both in T2* and Apparent Diffusivitiy across the cohort.

CONCLUSIONS

This first exploration of functional placental assessment in a cohort of women with PPROM demonstrates that functional placental MRI can reveal a range of placental changes associated with inflammatory processes. It is a promising tool to gain information and in the future to identify inflammation in vivo, and could therefore assist in improving optimal timing for interventions designed to prevent fetal injury.

Maternal cardiovascular disease after twin pregnancies complicated by hypertensive disorders of pregnancy: a population-based cohort study

Background:

People whose singleton pregnancy is affected by hypertensive disorders of pregnancy (HDP) are at risk of future cardiovascular disease. It is unclear, however, whether this association can be extrapolated to twin pregnancies. We aimed to compare the association between HDP and future cardiovascular disease after twin and singleton pregnancies.

Methods:

We conducted a population-based retrospective cohort study that included nulliparous people in Ontario, Canada, 1992–2017. We compared the future risk of cardiovascular disease among pregnant people from the following 4 groups: those who delivered a singleton without HDP (referent) and with HDP, and those who delivered twins either with or without HDP.

Results:

The populations of the 4 groups were as follows: 1 431 651 pregnant people in the singleton birth without HDP group; 98 631 singleton birth with HDP; 21 046 twin birth without HDP; and 4283 twin birth with HDP. The median duration of follow-up was 13 (interquartile range 7–20) years. The incidence rate of cardiovascular disease was lowest among those with a singleton or twin birth without HDP (0.72 and 0.74 per 1000 person-years, respectively). Compared with people with a singleton birth without HDP, the risk of cardiovascular disease was highest among those with a singleton birth and HDP (1.47 per 1000 person-years; adjusted hazard ratio [HR] 1.81 [95% confidence interval (CI) 1.72–1.90]), followed by people with a twin pregnancy and HDP (1.07 per 1000 person-years; adjusted HR 1.36 [95% CI 1.04–1.77]). The risk of the primary outcome after a twin pregnancy with HDP was lower than that after a singleton pregnancy with HDP (adjusted HR 0.74 [95% CI 0.57–0.97]), when compared directly.

Interpretation:

In a twin pregnancy, HDP are weaker risk factors for postpartum cardiovascular disease than in a singleton pregnancy.

Fetal Growth Restriction: Does an Integrated Maternal Hemodynamic-Placental Model Fit Better?

In recent years, a growing interest has arisen regarding the possible relationship between adverse pregnancy outcomes (APOs) and inadequate maternal hemodynamic adaptations to the pregnancy. A possible association between "placental syndromes," such as preeclampsia (PE) and fetal growth restriction (FGR), and subsequent maternal cardiovascular diseases (CVD) later in life has been reported. The two subtypes of FGR show different pathogenetic and clinical features. Defective placentation, due to a poor trophoblastic invasion of the maternal spiral arteries, is believed to play a central role in the pathogenesis of early-onset PE and FGR. Since placental functioning is dependent on the maternal cardiovascular system, a pre-existent or subsequent cardiovascular impairment may play a key role in the pathogenesis of early-onset FGR. Late FGR does not seem to be determined by a primary abnormal placentation in the first trimester. The pathological pathway of late-onset FGR may be due to a primary maternal cardiovascular maladaptation: CV system shows a flat profile and remains similar to those of non-pregnant women. Since the second trimester, when the placenta is already developed and increases its functional request, a hypovolemic state could lead to placental hypoperfusion and to an altered maturation of the placental villous tree and therefore to an altered fetal growth. Thus, this review focalizes on the possible relationship between maternal cardiac function and placentation in the development of both early and late-onset FGR. A better understanding of maternal hemodynamics in pregnancies complicated by FGR could bring various benefits in clinical practice, improving screening and therapeutic tools.

Preventable stillbirths in India and Pakistan: a prospective, observational study

OBJECTIVE

Stillbirths occur 10-20 times more frequently in low-income settings compared with high-income settings. We created a methodology to define the proportion of stillbirths that are potentially preventable in low-income settings and applied it to stillbirths in sites in India and Pakistan.

DESIGN

Prospective observational study.

SETTING

Three maternity hospitals in Davangere, India and a large public hospital in Karachi, Pakistan.

POPULATION

All cases of stillbirth at ≥20 weeks of gestation occurring from July 2018 to February 2020 were screened for participation; 872 stillbirths were included in this analysis.

METHODS

We prospectively defined the conditions and gestational ages that defined the stillbirth cases considered potentially preventable. Informed consent was sought from the parent(s) once the stillbirth was identified, either before or soon after delivery. All information available, including obstetric and medical history, clinical course, fetal heart sounds on admission, the presence of maceration as well as examination of the stillbirth after delivery, histology, and polymerase chain reaction for infectious pathogens of the placenta and various fetal tissues, was used to assess whether a stillbirth was potentially preventable.

MAIN OUTCOME MEASURES

Whether a stillbirth was determined to be potentially preventable and the criteria for assignment to those categories.

RESULTS

Of 984 enrolled, 872 stillbirths at ≥20 weeks of gestation met the inclusion criteria and were included; of these, 55.5% were deemed to be potentially preventable. Of the 649 stillbirths at ≥28 weeks of gestation and ≥1000 g birthweight, 73.5% were considered potentially preventable. The most common conditions associated with a potentially preventable stillbirth at ≥28 weeks of gestation and ≥1000 g birthweight were small for gestational age (SGA) (52.8%), maternal hypertension (50.2%), antepartum haemorrhage (31.4%) and death that occurred after hospital admission (15.7%).

CONCLUSIONS

Most stillbirths in these sites were deemed preventable and were often associated with maternal hypertension, antepartum haemorrhage, SGA and intrapartum demise.

TWEETABLE ABSTRACT

Most stillbirths are preventable by better care for women with hypertension, growth restriction and antepartum haemorrhage.

The association between maternal placental growth factor and placental maternal vascular malperfusion lesions

INTRODUCTION

Placental Growth Factor (PlGF) is used for the prediction of preeclampsia (PE), a syndrome associated with maternal vascular malperfusion (MVM). Our goal is to determine the correlation between PlGF and MVM.

MATERIAL AND METHODS

We performed a secondary analysis of the PEARL study that included nulliparous women with PE (cases), and low-risk nulliparous women recruited in early pregnancy (controls). All participants provided blood samples at diagnosis of PE (cases), or between 26 and 34 weeks (controls) for measurement of PlGF (B·R·A·H·M·S plus KRYPTOR automated assays), that was transformed into multiple of median (MoM). Placental examination was performed for the diagnosis of MVM based on the Amsterdam Placental Workshop Group Consensus Statement. Nonparametric tests and receiver operating characteristic (ROC) curves were used to compare PlGF in pregnancies with, and without PE, stratified by the presence of MVM.

RESULTS

Third trimester PlGF was lower in PE cases with MVM (N = 20; median: 0.04 MoM; interquartile: 0.03-0.09; p<0.0001), and in controls with MVM (N = 4; 0.30MoM; 0.07-0.52; p = 0.002) compared to controls without MVM (N = 29; 0.99 MoM; 0.67-1.52). PlGF in PE cases without MVM (N = 5; 0.18 MoM; 0.17-1.64) was not significantly different than in controls without MVM but the sample size was small. ROC curve demonstrated a greater predictability of PlGF for PE with MVM than PE without MVM (AUC: 0.99 vs. 0.38; p<0.0001).

DISCUSSION

Third trimester PlGF is a better predictor of PE associated with MVM than a predictor of PE without MVM. We hypothesize that PlGF is a stronger marker of MVM than PE.

Circulating angiogenic profiles and histo-morphological placental characteristics of uncomplicated post-date pregnancies

INTRODUCTION

The objectives of this study were to describe the histo-morphology of post-date placentas in clinically uncomplicated pregnancies without adverse delivery outcomes and the association with maternal circulating pre-delivery Placental Growth Factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1), as well as the sFlt-1/PlGF ratio.

METHODS

Post-date placentas (gestational week ≥40⁺², n = 87) were macroscopically and histo-morphologically assessed according to the international, standardized Amsterdam Workshop Consensus Group criteria. Inter-rater agreement was evaluated by percentage of agreement. PlGF and sFlt-1 concentrations were available from maternal serum sampled close to delivery, and were compared by Mann-Whitney U test. Linear regression analyses were adjusted for predefined potential confounders.

RESULTS

The majority of the post-date placentas showed morphological signs of delayed maturation. About half of the placentas showed increased syncytial knotting and fibrin. In placentas with increased presence of intervillous fibrin, median maternal PlGF level was significantly lower (p = 0.004), median sFlt-1 level higher and sFlt-1/PlGF ratio significantly higher (p = 0.002) compared to those with normal fibrin amounts. Increased placental syncytial knotting was associated with lower levels of PlGF, higher sFlt-1 and higher sFlt-1/PlGF ratio compared to those with normal knotting.

DISCUSSION

Our standardized morphological study of post-date placentas in clinically healthy women with uncomplicated pregnancies and delivery outcomes revealed delayed maturation in the majority of placentas. Increased pre-delivery circulating anti-angiogenic profile was associated with increased intervillous fibrin and syncytial knotting. We propose that circulating maternal angiogenic biomarkers may be of future use in clinical post-date pregnancy assessment, as they reflect important aspects of placental health and function.

Second Trimester Placental Growth Factor Levels and Placental Histopathology in Low-Risk Nulliparous Pregnancies

OBJECTIVE

Placental growth factor (PlGF) levels are lower at delivery in pregnancies with preeclampsia or fetuses small for gestational age (SGA). These obstetrical complications are typically mediated by placental dysfunction, most commonly related to the specific placental phenotype termed placental maternal vascular malperfusion (MVM). The objective of this study was to determine the relationship between PlGF levels in the second trimester and the development of placental diseases that underlie adverse perinatal outcomes.

METHODS

We performed a secondary analysis of the prospective Placental Health Study in unselected healthy nulliparous women (n = 773). Maternal demographic data, Doppler ultrasound measurements, and plasma PlGF levels at 15 to 18 weeks gestation were analyzed for association with pregnancy outcomes and placental pathology following delivery.

RESULTS

Low PlGF levels in the second trimester (<10th percentile; <72 pg/mL) was associated with preterm delivery (<37 weeks; 26% vs. 6%, P < 0.001; unadjusted odds ratio (OR) 5.75, 95% CI 3.2-10.5), reduced mean birthweight (2998 vs. 3320 g, P < 0.001), SGA deliveries (25% vs. 11%, P = 0.001; OR 2.6, 95% CI 1.5-4.6), and preeclampsia (7% vs. 2%, P = 0.02; OR 4.3, 95% CI 1.5-12.8) relative to normal PlGF levels (≥10th percentile; ≥72 pg/mL). Low PlGF was associated with lower mean placental weight (447 vs. 471 g, P = 0.01), aberrant cord insertion (25% vs. 12%, P = 0.001) and a pathologic diagnosis of MVM (18% vs. 11%, P = 0.04; OR 1.9, 95% CI 1.01-3.55) but not with other placental pathologies.

CONCLUSION

MVM placental pathology and related adverse perinatal outcomes are associated with low PlGF in the early second trimester for healthy nulliparous women.

Fetal Growth Restriction in Hypertensive vs. Heavy Smoking Women-Placental Pathology, Ultrasound Findings, and Pregnancy Outcomes

We compared placental pathology, ultrasonographic findings, and obstetric outcomes, in gestations complicated by fetal growth restriction (FGR) with either a background of hypertensive disorder or heavy tobacco cigarette smoking. The medical records and placental pathology reports of pregnancies complicated with FGR (birthweight < 10th percentile) between December 2008 and May 2018 from a single tertiary center were reviewed. Placental pathology, ultrasound findings, and pregnancy outcomes were compared between hypertensive patients (HTN) and heavy smokers (SMO). We included 213 pregnancies: 129 (60.6%) in the SMO group and 84 (39.4%) in the HTN group. The HTN group was characterized by a higher BMI (p = 0.01), higher rates of Cesarean deliveries (p = 0.006), and a lower gestational age at delivery (35.6 ± 3.8 vs. 37.5 ± 2.9 weeks, p < 0.001). The HTN group had higher rates of placental weights < 10th percentile (p = 0.04) and maternal vascular malperfusion lesions (p < 0.001), while the SMO group had higher rates of inflammatory lesions (p = 0.04). On ultrasound, the HTN group had a higher head/abdomen circumference ratio (p < 0.001) and more abnormal Doppler studies (< 0.001). Neonates in the HTN group had lower birthweights (p < 0.001) and higher rates of NICU admissions (p = 0.002) and adverse neonatal outcome (p = 0.006). On multivariable analysis, gestational age at delivery (aOR = 0.65, 95%CI 0.55-0.87), hypertensive disorders (aOR = 1.8, 95%CI = 1.21-4.81), placental MVM lesions (aOR = 1.23, 95%CI = 1.08-5.02), and the combination of HTN+MVM (aOR = 2.63, 95%CI 1.78-7.30) were independently associated with adverse neonatal outcome. Hypertension and smoking may lead to FGR in different pathways as the two groups significantly differed in maternal characteristics, placental pathology, ultrasound findings, and neonatal outcomes. A hypertensive disorder probably represents a more hostile maternal environment than smoking and these pregnancies would probably benefit from closes monitoring.

Placental abruption as a trigger of DIC in women with HELLP syndrome: a population-based study

BACKGROUND

Disseminated Intravascular Coagulation (DIC) is a life-threatening condition. Hemolysis, Elevated Liver enzymes and Low Platelets (HELLP) syndrome is one of the obstetrical syndromes mostly associated with DIC and thus, high rates of fatal complications. There is a lack of information regarding epidemiologic and clinical characteristics of women who developed HELLP syndrome with and without DIC. Additionally, until now, there is no adapted and widely accepted way to diagnose DIC among pregnant women presenting with HELLP syndrome, despite the evident maternal mortality linked to the disease.

Objectives: (1) Address the gaps in knowledge regarding the prevalence, epidemiologic and clinical characteristics of women with HELLP syndrome who develop DIC; and (2) determine the risk factors for the development of DIC among women with HELLP syndrome.

STUDY DESIGN

This was a population-based retrospective cohort study, including all women who delivered at the Soroka University Medical Center between the years 2001-2017. The study population was divided into three groups: (1) comparison group (n = 207,266 deliveries); (2) HELLP syndrome without DIC (n = 320); (3) HELLP syndrome with DIC (n = 21). The diagnosis of DIC was based on the ICD-9 code as recorded in the obstetrical database of the Soroka University Medical Center. The coding is based on the diagnosis made by the attending physician during hospitalization.

RESULTS

(1) The rate of HELLP syndrome in the study population was 0.16% (341/207,607), of them 6.16% (21/341) had DIC; (2) among patients with HELLP syndrome, those with DIC had a higher median gravidity and parity; (3) a higher rate of severe maternal morbidity including blood product transfusion, placental abruption, eclampsia, acute renal failure and maternal death was observed in those who had HELLP syndrome and DIC compared to those with HELLP syndrome without DIC and the comparison group (p-value <.001 for comparison among the three groups); (4) among women with HELLP syndrome, those with DIC had a longer median PT difference, higher serum creatinine and lower AST as well as ALT median concentrations than those without DIC; (5) patients with HELLP syndrome and DIC had a higher rate of stillbirth and postpartum death than patients in the other groups (p-value <.001 for comparison among the three groups); and (6) placental abruption was an independent risk factor for the development of DIC in women with HELLP syndrome (p-value <.001).

CONCLUSIONS

(1) Among women with HELLP syndrome, those who developed DIC had a higher rate of maternal and neonatal morbidity and mortality than those without DIC; and (2) placental abruption, but not abnormal liver function, was an independent risk factor for the development of DIC in women with HELLP syndrome.

Associations Between Placental Corticotropin-Releasing Hormone, Maternal Cortisol, and Birth Outcomes, Based on Placental Histopathology

Preterm birth remains the leading cause of neonatal morbidity and mortality, with complex biochemical pathways requiring continued understanding and assessment. The objective of this study is to assess the associations between maternal cortisol and placental corticotropin-releasing hormone (placental CRH) concentrations with birth outcomes when stratified by placental histopathology. We conducted an analysis of 112 singleton pregnancies who received betamethasone between 23 and 34 weeks' gestation. Maternal blood and saliva were collected prior to betamethasone administration and samples assayed for plasma cortisol (pCort), salivary cortisol (sCort), and placental CRH levels. Placental findings were characterized as inflammatory, maternal vascular underperfusion (MVU), or no pathology, and compared for the outcomes of placental CRH, pCort, and sCort levels, gestational age at birth (GAB), and birthweight percentiles (BWP). Thirty-six subjects were characterized as inflammatory, 38 as MVU, and 38 without placental abnormalities. Histopathology groups differed significantly on placental CRH levels, GAB, and BWP. Post hoc tests suggested that the MVU group had higher placental CRH than the inflammatory or no pathology groups, and despite delivering earlier than the other two groups, the inflammatory group had infants with significantly higher BWP. No differences existed between groups in terms of mean plasma or sCort levels. Higher placental CRH and pCort levels were associated with earlier GAB in the overall sample, but when split by group, these associations remained significant only among the MVU group. Higher placental CRH was also associated with lower BWP in the overall sample but did not remain significant when split by group. Higher sCort was associated with lower BWP only in the MVU group. There is differentiation of placental CRH, cortisol, and birth outcomes when evaluated by placental histopathology. This highlights the importance of evaluating birth outcomes within the context of placental histopathology.

Circulating SPINT1 is a biomarker of pregnancies with poor placental function and fetal growth restriction

Placental insufficiency can cause fetal growth restriction and stillbirth. There are no reliable screening tests for placental insufficiency, especially near-term gestation when the risk of stillbirth rises. Here we show a strong association between low circulating plasma serine peptidase inhibitor Kunitz type-1 (SPINT1) concentrations at 36 weeks' gestation and low birthweight, an indicator of placental insufficiency. We generate a 4-tier risk model based on SPINT1 concentrations, where the highest risk tier has approximately a 2-5 fold risk of birthing neonates with birthweights under the 3^rd, 5^th, 10^th and 20^th centiles, whereas the lowest risk tier has a 0-0.3 fold risk. Low SPINT1 is associated with antenatal ultrasound and neonatal anthropomorphic indicators of placental insufficiency. We validate the association between low circulating SPINT1 and placental insufficiency in two other cohorts. Low circulating SPINT1 is a marker of placental insufficiency and may identify pregnancies with an elevated risk of stillbirth.

Placental histopathology in sickle cell disease: A descriptive and hypothesis-generating study

INTRODUCTION

Abnormal placental development is a unifying factor amongst many adverse pregnancy outcomes (APOs) in Sickle Cell Disease (SCD). Our aim was to describe placental histopathologic findings in women with SCD and their relationship with APOs, and to explore the association between antenatal sonographic findings and placental pathology.

METHODS

Retrospective single-centre case series of all pregnant women with SCD (January 2000-December 2017), pregnancy beyond 20 weeks' gestation, and available placenta histopathology. APOs included intrauterine fetal death, early neonatal death, preterm birth, small for gestational age, and hypertensive disorders of pregnancy. Review of images for mid-pregnancy ultrasound and one proximal to delivery was completed, blinded to clinical outcomes and histopathology results. Gross and histopathologic findings were reviewed and characterized per published classification.

RESULTS

Of 72 placentas, abnormalities were present in 69%, with Maternal Vascular Malperfusion (MVM) noted in 40%. APOs were encountered in 61% overall and in 79% of those with MVM. Neither SCD genotype nor severe maternal anemia had an influence on histopathologic placental features. Presence of high-resistance uterine artery waveforms at mid-trimester ultrasound was strongly associated with APOs and with abnormal findings on placental histopathology, most notably MVM. MVM was strongly associated with small for gestational age infants, preterm birth, and stillbirth.

DISCUSSION

MVM is the predominant lesion in placentas of women with SCD and is strongly associated with APOs. Mid-trimester ultrasound can identify a subset of women at risk. Future research into advanced imaging modalities to aid in antenatal diagnosis alongside investigations of potentially beneficial therapies is needed.

Novel Strategies to Reduce Pulmonary Hypertension in Infants With Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is a developmental lung disorder of preterm infants primarily caused by the failure of host defense mechanisms to prevent tissue injury and facilitate repair. This disorder is the most common complication of premature birth, and its incidence remains unchanged over the past few decades. Additionally, BPD increases long-term cardiopulmonary and neurodevelopmental morbidities of preterm infants. Pulmonary hypertension (PH) is a common morbidity of BPD. Importantly, the presence of PH increases both the short- and long-term morbidities and mortality in BPD infants. Further, there are no curative therapies for this complex disease. Besides providing an overview of the pathogenesis and diagnosis of PH associated with BPD, we have attempted to comprehensively review and summarize the current literature on the interventions to prevent and/or mitigate BPD and PH in preclinical studies. Our goal was to provide insight into the therapies that have a high translational potential to meaningfully manage BPD patients with PH.

The Placental Basis of Fetal Growth Restriction

Placental dysfunction is a major contributing factor to fetal growth restriction. Placenta-mediated fetal growth restriction occurs through chronic fetal hypoxia owing to poor placental perfusion through a variety of mechanisms. Maternal vascular malperfusion is the most common placental disease contributing to fetal growth restriction; however, the role of rare placental diseases should not be overlooked. Although the features of maternal vascular malperfusion are identifiable on placental pathology, antepartum diagnostic methods are evolving. Placental imaging and uterine artery Doppler, used in conjunction with angiogenic growth factors (specifically placenta growth factor and soluble fms-like tyrosine kinase-1), play an increasingly important role.

No association between early antiretroviral therapy during pregnancy and plasma levels of angiogenic factors: a cohort study

Background

Early antiretroviral therapy (ART) during pregnancy has dramatically reduced the risk of perinatal HIV transmission. However, studies have shown an association between premature delivery and the use of ART during pregnancy (particularly protease inhibitor (PI)-based therapies), which could be explained by placental dysfunction. The objective of this study was to evaluate the association of ART (class, duration of exposure and time of initiation) with placental function by using angiogenic factors placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1) as biomarkers.

Methods

Clinical and biological data from 159 pregnant women living with HIV were analyzed. Levels of each biomarker were measured in the first and second trimester of pregnancy. After logarithmic transformation, we compared these using generalized estimating equations according to (a) the type of ART; (b) the duration of exposure to ART; and (c) the time of initiation of ART.

Results

After adjusting for variables such as ethnicity, maternal age, gestational age, body mass index, parity, smoking status, and sex of the fetus, we found no significant association between the class of ART (PI-based or not) and serum concentrations of PlGF or sFlt-1. Furthermore, no significant association was found between biomarker levels and the duration of ART exposure or the timing of ART initiation (pre- or post-conception).

Conclusions

This study suggests that first and second trimester angiogenic factor levels are not significantly associated with ART, regardless of the duration or type (with or without PI). These observations seem reassuring when considering the use of ART during early pregnancy.

Impact of parturition on maternal cardiovascular and neuronal integrity in a high risk cohort - a prospective cohort study

Background

To better understand the profound multisystem changes in maternal physiology triggered by parturition, in particular in the underexplored neuronal system, by deploying a panel of pre- vs post-delivery maternal serum biomarkers, most notably the neuronal cytoskeleton constituent neurofilament light chain (NfL). This promising fluid biomarker is not only increasingly applied to investigate disease progression in numerous brain diseases, particularly in proteopathies, but also in detection of traumatic brain injury or monitoring neuroaxonal injury after ischemic stroke.

Methods

The study was nested within a prospective cohort study of pregnant women at risk of developing preeclampsia at the University Hospital of Basel. Paired ante- and postpartum levels of progesterone, soluble fms-like tyrosine kinase-1 (sFlt-1), placental growth factor (PlGF), mid-regional pro-atrial natriuretic peptide (MR-proANP), copeptin (CT-proAVP), and NfL were measured in 56 women with complete clinical data.

Results

Placental delivery significantly decreased all placental markers: progesterone 4.5-fold, PlGF 2.2-fold, and sFlt-1 1.7-fold. Copeptin and MR-proANP increased slightly (1.4- and 1.2-fold, respectively). Unexpectedly, NfL levels (median [interquartile range]) increased significantly post-partum: 49.4 (34.7–77.8) vs 27.7 (16.7–31.4) pg/ml (p < 0.0001). Antepartum NfL was the sole independent predictor of NfL peri-partum change; mode of delivery, duration of labor, clinical characteristics and other biomarkers were all unrelated. Antepartum NfL levels were themselves independently predicted only by maternal age.

Conclusions

Parturition per se increases maternal serum NfL levels, suggesting a possible impact of parturition on maternal neuronal integrity.