Placental villous hypermaturation is associated with idiopathic preterm birth

Systemic lupus erythematosus is associated with an increased frequency of spontaneous preterm births: systematic review and meta-analysis

OBJECTIVE

Preterm birth is one of the most frequent complications of pregnancy in women with systemic lupus erythematosus. The high indicated preterm birth proportion due to hypertensive disorders of pregnancy and/or fetal growth restriction is well known, and preventive measures and screening for early detection are performed. The risk of spontaneous preterm birth is less well recognized. This study aimed to determine the proportions of spontaneous and indicated preterm birth in pregnancies of women with systemic lupus erythematosus.

DATA SOURCES

A systematic literature search using Pubmed, Embase, Web of Science, and Google Scholar was performed in June 2021.

STUDY ELIGIBILITY CRITERIA

Studies in pregnant women with systemic lupus erythematosus reporting spontaneous and indicated preterm birth rates were selected. Original research articles published from 1995 to June 2021 were included.

METHODS

Quality and risk of bias of the included studies were assessed using the Newcastle-Ottawa quality assessment scale. To estimate the pooled event rates and 95% confidence intervals, meta-analysis of single proportions with a random-effects model was performed.

RESULTS

We included 21 articles, containing data of 8157 pregnancies in women with systemic lupus erythematosus. On average, 31% (95% prediction interval, 0.14-0.50) of the pregnancies resulted in preterm birth, including 14% (95% prediction interval, 0.04-0.27) spontaneous and 16% (95% prediction interval, 0.03-0.35) indicated preterm birth.

CONCLUSION

In pregnant women with systemic lupus erythematosus, spontaneous and indicated preterm birth proportions are high. This information should be applied in (prepregnancy) counseling and management in pregnancy. The knowledge obtained by this meta-analysis paves the way for further research of associated risk factors and development of interventions to reduce spontaneous preterm birth in systemic lupus erythematosus pregnancies.

Sickle cell disease and increased adverse maternal and perinatal outcomes in different genotypes

BACKGROUND

Sickle cell disease (SCD) comprises a heterogeneous group of inherited hemolytic disorders that increases the risk of maternal and perinatal complications due to chronic systemic inflammatory response, endothelial damage and vaso-occlusion. The contribution of genotypes to the severity of outcomes during pregnancy is not completely established.

METHODS

A retrospective study of medical charts was performed to compare maternal and perinatal outcomes in Hb SS, Hb SC disease and sickle-beta thalassemia (Hb Sβ) pregnancies followed at a high-risk antenatal care unit over a 6-year period. A descriptive analysis of morphological findings was performed of the placenta when pathology reports were available.

RESULTS

Sixty-two SCD pregnant women [25 Hb SS (40 %), 29 Hb SC (47 %) and 8 Hb Sβ (13 %)] were included. Overall, SCD was associated with maternal complications (77 %), preterm birth (30 %), cesarean section (80 %) and a need of blood transfusion. In general there were no statistically significant differences between genotypes. The only significant difference was the hemoglobin level at first antenatal care visit which was lower for the homozygous genotype (7.7 g/dL) compared to Hb SC and Hb Sβ (9.7 g/dL and 8.4 g/dL, respectively; p-value = 0.01). Ten of 15 evaluated placentas showed abnormal morphological findings CONCLUSION: SCD, regardless of the underlying genotype, is associated with increased adverse maternal and perinatal outcomes and placental abnormalities associated with maternal vascular malperfusion.

Placental differences between severe fetal growth restriction and hypertensive disorders of pregnancy requiring early preterm delivery: morphometric analysis of the villous tree supported by artificial intelligence

BACKGROUND

The great obstetrical syndromes of fetal growth restriction and hypertensive disorders of pregnancy can occur individually or be interrelated. Placental pathologic findings often overlap between these conditions, regardless of whether 1 or both diagnoses are present. Quantification of placental villous structures in each of these settings may identify distinct differences in developmental pathways.

OBJECTIVE

This study aimed to determine how the quantity and surface area of placental villi and vessels differ between severe, early-onset fetal growth restriction with absent or reversed umbilical artery Doppler indices and hypertensive disorders of pregnancy or the 2 conditions combined among subjects with disease severity that warrant early preterm delivery. We hypothesized that the trajectories of placental morphogenesis diverge after a common initiating insult of deep defective placentation. Specifically, we postulated that only villi are affected in pregnancy-related hypertension, whereas both villous and vascular structures are proportionally diminished in severe fetal growth restriction with no additional effect when hypertension is concomitantly present.

STUDY DESIGN

In this retrospective cohort study, paraffin-embedded placental tissue was obtained from 4 groups, namely (1) patients with severe fetal growth restriction with absent or reversed umbilical artery end-diastolic velocities and hypertensive disorders of pregnancy, (2) patients with severe fetal growth restriction with absent or reversed umbilical artery Doppler indices and no hypertension, (3) gestational age-matched, appropriately grown pregnancies with hypertensive disease, and (4) gestational age-matched, appropriately grown pregnancies without hypertension. Dual immunohistochemistry for cytokeratin-7 (trophoblast) and CD34 (endothelial cells) was performed, followed by artificial intelligence-driven morphometric analyses. The number of villi, total villous area, number of fetoplacental vessels, and total vascular area across villi within a uniform region of interest were quantified. Quantitative analyses of placental structures were modeled using linear regression.

RESULTS

Placentas from pregnancies complicated by hypertensive disorders of pregnancy exhibited significantly fewer stem villi (-282 stem villi; 95% confidence interval, -467 to -98; P<.01), a smaller stem villous area (-4.3 mm2; 95% confidence interval, -7.3 to -1.2; P<.01), and fewer stem villous vessels (-4967 stem villous vessels; 95% confidence interval, -8501 to -1433; P<.01) with no difference in the total vascular area. In contrast, placental abnormalities in cases with severe growth restriction were limited to terminal villi with global decreases in the number of villi (-873 terminal villi; 95% confidence interval, -1501 to -246; P<.01), the villous area (-1.5 mm2; 95% confidence interval, -2.7 to -0.4; P<.01), the number of blood vessels (-5165 terminal villous vessels; 95% confidence interval, -8201 to -2128; P<.01), and the vascular area (-0.6 mm2; 95% confidence interval, -1.1 to -0.1; P=.02). The combination of hypertension and growth restriction had no additional effect beyond the individual impact of each state.

CONCLUSION

Pregnancies complicated by hypertensive disorders of pregnancy exhibited defects in the stem villi only, whereas placental abnormalities in severely growth restricted pregnancies with absent or reversed umbilical artery end-diastolic velocities were limited to the terminal villi. There were no significant statistical interactions in the combination of growth restriction and hypertension, suggesting that distinct pathophysiological pathways downstream of the initial insult of defective placentation are involved in each entity and do not synergize to lead to more severe pathologic consequences. Delineating mechanisms that underly the divergence in placental development after a common inciting event of defective deep placentation may shed light on new targets for prevention or treatment.

Stillbirth and the placenta

Stillbirth affects a large proportion of pregnancies world-wide annually and continues to be a major public health concern. Several causes of stillbirth have been identified and include obstetrical complications, placental abnormalities, fetal malformations, infections, and medical complications in pregnancy. Placental abnormalities such as placental abruption, chorioangioma, vasa previa, and umbilical cord abnormalities have been identified as causes of death for a significant proportion of stillbirths. In the absence of placental abnormalities, the gross and histologic changes in the placenta in stillbirth are found when secondary to other etiologies. Here we describe both gross and histologic changes of the placenta that are associated with stillbirth.

Fetal spina bifida associates with dysregulation in nutrient-sensitive placental gene networks: Findings from a matched case-control study

To improve outcomes in fetuses with spina bifida (SB), better understanding is needed of the molecular drivers of SB and its comorbidities. Pregnant people carrying a fetus with isolated SB (cases; n = 12) or a fetus with no congenital anomalies (controls; n = 21) were recruited at Mount Sinai Hospital, Toronto, Ontario, Canada. Clinical data and placental samples were collected. Placental transcriptome was sequenced (Clariom D microarray) and a nutrient-focused gene expression analysis pipeline was applied to determine whether fetal SB associates with placental dysfunction. Of the 391 differentially expressed genes (DEGs) in cases, 11% (n = 42) had at least one nutrient cofactor, including B vitamins (n = 7 genes), iron/heme (n = 6), and zinc (n = 11). Cases had dysregulation in genes not previously known to associate with SB, and in placental genes that have known links to SB but have not been previously identified in the placenta. Cases also had downregulated nutrient transport and upregulated branching angiogenesis and immune/inflammatory processes. Five nutrient-dependent transcription regulators, collectively predicted to target 46% of DEGs in cases, were identified and were most commonly dependent on B vitamins (n = 3) and zinc (n = 2). Placental gene expression changes were most acute in cases with poor growth. Placentae from fetuses with SB have dysregulation in several gene networks, including those that are sensitive to multiple micronutrients beyond the well-known folic acid. An improved understanding of placental phenotype in fetuses with SB may help identify novel mechanisms associated with comorbidities in fetuses with SB, and reveal new targets to improve fetal outcomes in this population.

Outcome-Based Risk Stratification Model for the Diagnosis of Placental Maternal Vascular Malperfusion

The Amsterdam Consensus Statement introduced the term maternal vascular malperfusion (MVM) to group a constellation of findings associated with impaired maternal-placental circulation. In isolation, these findings are relatively common in placentas from normal gestations, and there is uncertainty on how many, and which, are required. We aimed to determine the criteria essential for MVM diagnosis in correlation with obstetrical outcomes. A total of 200 placentas (100 with a reported diagnosis of MVM and 100 controls matched by maternal age and gravida-para-abortus status) were reviewed to document MVM features. Obstetrical outcomes in the current pregnancy were recorded including hypertension, pre-eclampsia with or without severe features, gestational diabetes, prematurity, fetal growth restriction, and intrauterine fetal demise. On univariate logistic regression analysis, adverse outcome was associated with low placental weight (LPW, <10% percentile for gestational age), accelerated villous maturation (AVM), decidual arteriopathy (DA), infarcts (presence and volume), distal villous hypoplasia, and excess multinucleated trophoblast in basal plate ≥2 mm (all P < .01) but not with retroplacental hemorrhage. In a multivariable model DA, infarcts and AVM were significantly associated with adverse outcomes, whereas LPW showed a trend toward significance. A receiver-operating characteristic curve including these 4 parameters showed good predictive ability (area under the curve [AUC], 0.8256). Based on the probability of an adverse outcome, we recommend consistent reporting of DA, AVM, infarcts, and LPW, summarizing them as "diagnostic of MVM" (DA or AVM plus any other feature, yielding a probability of 65%-97% for adverse obstetrical outcomes) or "suggestive of MVM" (if only 1 feature is present, or only 2 features are infarcts plus LPW, yielding a probability of up to 52%). Other features such as distal villous hypoplasia, excess (≥2 mm) multinucleated trophoblast, and retroplacental hemorrhage can also be reported, and their role in MVM diagnosis should be further studied.

Effect of Parity on Placental Histopathology Features in Singleton Live Births Following IVF

The aim of this study was to evaluate the effect of parity (primipara vs multipara) on the histopathology of the placenta in singleton live births following in vitro fertilization. We conducted a retrospective cohort study evaluating data of all IVF resulted live births from one university affiliated hospital during 2009-2017. All patients had the placenta sent for pathological evaluation. Exclusion criteria were history of miscarriage or elective termination of pregnancy, abnormal uterine cavity findings, previous uterine surgery, in vitro maturation cycles, gestational carrier cycles, oocyte recipient cycles, preimplantation genetic diagnosis cycles, and multiple pregnancies. The outcomes measured included anatomical, inflammation, vascular malperfusion, and villous maturation placental features. A multivariate analysis was conducted to adjust the results for factors potentially associated with placental pathology features. A total of 395 live births were included in the final analysis and were allocated to the study groups according to parity: primipara (n = 273) and multipara (n = 122). After adjustment for potential confounding factors, multiparity was found to be significantly associated with delayed villous maturation (OR 4.9; 95% CI 1.2-19.8) and primiparity was significantly associated with maternal vascular malperfusion (OR 0.6; 95% CI 0.3-0.8). We showed that parity has an impact on placental histopathological changes which in turn may affect perinatal outcome.

Transcriptomic analysis of the human placenta reveals trophoblast dysfunction and augmented Wnt signalling associated with spontaneous preterm birth

Preterm birth (PTB) is the leading cause of death in under-five children. Worldwide, annually, over 15 million babies are born preterm and 1 million of them die. The triggers and mechanisms of spontaneous PTB remain largely unknown. Most current therapies are ineffective and there is a paucity of reliable predictive biomarkers. Understanding the molecular mechanisms of spontaneous PTB is crucial for developing better diagnostics and therapeutics. To address this need, we conducted RNA-seq transcriptomic analysis, qRT-PCR and ELISA on fresh placental villous tissue from 20 spontaneous preterm and 20 spontaneous term deliveries, to identify genes and signalling pathways involved in the pathogenesis of PTB. Our differential gene expression, gene ontology and pathway analysis revealed several dysregulated genes (including OCLN, OPTN, KRT7, WNT7A, RSPO4, BAMBI, NFATC4, SLC6A13, SLC6A17, SLC26A8 and KLF8) associated with altered trophoblast functions. We identified dysregulated Wnt, oxytocin and cellular senescence signalling pathways in preterm placentas, where augmented Wnt signalling could play a pivotal role in the pathogenesis of PTB due to its diverse biological functions. We also reported two novel targets (ITPR2 and MYLK2) in the oxytocin signalling pathways for further study. Through bioinformatics analysis on DEGs, we identified four key miRNAs, - miR-524-5p, miR-520d-5p, miR-15a-5p and miR-424-5p - which were significantly downregulated in preterm placentas. These miRNAs may have regulatory roles in the aberrant gene expressions that we have observed in preterm placentas. We provide fresh molecular insight into the pathogenesis of spontaneous PTB which may drive further studies to develop new predictive biomarkers and therapeutics.

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.

Dysregulation of integrin αvβ3 and α5β1 impedes migration of placental endothelial cells in fetal growth restriction

Placentas from pregnancies complicated by severe early-onset fetal growth restriction (FGR) exhibit diminished vascular development mediated by impaired angiogenesis, but underlying mechanisms remain unknown. In this study, we show that FGR endothelial cells demonstrate inherently reduced migratory capacity despite the presence of fibronectin, a matrix protein abundant in placental stroma that displays abnormal organization in FGR placentas. Thus, we hypothesized that aberrant endothelial-fibronectin interactions in FGR are a key mechanism underlying impaired FGR endothelial migration. Using human fetoplacental endothelial cells isolated from uncomplicated term control and FGR pregnancies, we assessed integrin α5β1 and αvβ3 regulation during cell migration. We show that endothelial integrin α5β1 and αvβ3 interactions with fibronectin are required for migration and that FGR endothelial cells responded differentially to integrin inhibition, indicating integrin dysregulation in FGR. Whole-cell expression was not different between groups. However, there were significantly more integrins in focal adhesions and reduced intracellular trafficking in FGR. These newly identified changes in FGR endothelial cellular processes represent previously unidentified mechanisms contributing to persistent angiogenic deficiencies in FGR.

Placental pathology in spontaneous and iatrogenic preterm birth: Different entities with unique pathologic features

INTRODUCTION

Placental pathology is an important contributor to the understanding of preterm birth and reveals major differences between spontaneous preterm birth (SPTB) and iatrogenic preterm birth (IPTB). The aim of this study was to investigate these relationships.

METHODS

Research midwives collected placentas from 1101 women with singleton pregnancies who were enrolled in the Safe Passage Study. Trained pathology technologists prepared and processed placenta specimens for macroscopic and microscopic examination by designated pathologists. Statistical analyses were done with STATISTICA version 13.

RESULTS

In SPTB we found more cases of accelerated villous maturation; however, the other features of maternal vascular malperfusion (MVM) were not present. The prevalence rate of funisitis was also increased. In IPTB, multiple features of MVM - accelerated villous maturation, distal villous hypoplasia, decidual arteriopathy, increased syncytial knots, increased perivillous fibrin, and prominent extravillous trophoblast were increased, as were features of fetal vascular malperfusion (FVM) - umbilical cord vessel thrombosis, avascular villi, and fetal vascular thrombosis. Increased syncytial knots were found in 26% of preterm stillbirths and in 29% of preterm infant demises as compared to 81% of IPTB infants alive at one year.

DISCUSSION

SPTB and IPTB differ. The detected "abnormal" accelerated villous maturation pattern in SPTB and preterm demises, suggests an inability of the placenta to adapt and may be a trigger for SPTB. Funisitis was the only inflammatory response significant for SPTB. MVM and FVM are implicated in IPTB, but not an inflammatory process.

Prediction of spontaneous preterm birth and preterm prelabor rupture of membranes using maternal factors, obstetric history and biomarkers of placental function at 11-13 weeks

OBJECTIVES

To determine whether first-trimester biomarkers of placental function can be used to screen for spontaneous preterm birth (sPTB), and to develop prediction models using maternal factors, obstetric history and biomarkers of placental function at 11-13 weeks for the calculation of patient-specific risk for sPTB.

METHODS

This was a retrospective secondary analysis of data derived from a prospective cohort study on first-trimester screening for pre-eclampsia in singleton pregnancies attending for routine Down syndrome screening at 11 + 0 to 13 + 6 weeks' gestation at a tertiary obstetric unit between December 2016 and September 2019. A split-sample internal validation method was used to explore and develop prediction models for all sPTB at < 37 weeks and for PTB at < 37 weeks after preterm prelabor rupture of membranes (PPROM) using maternal risk factors, uterine artery Doppler indices, serum placental growth factor (PlGF), pregnancy-associated plasma protein-A (PAPP-A) and β-human chorionic gonadotropin (β-hCG). Screening performance was assessed using receiver-operating-characteristics (ROC)-curve analysis, with calculation of the areas under the ROC curves (AUCs).

RESULTS

A total of 9298 singleton pregnancies were included in this study. sPTB at < 37 weeks occurred in 362 (3.89%) cases, including 231 (2.48%) cases of PPROM. sPTB at < 34 weeks occurred in 87 (0.94%) cases, including 39 (0.42%) cases of PPROM. Identified maternal risk factors for sPTB at < 37 weeks included chronic hypertension, conception using in-vitro fertilization and history of PTB. Maternal risk factors for PPROM at < 37 weeks included conception using in-vitro fertilization and history of PTB. Median PlGF multiples of the median (MoM) and PAPP-A MoM were significantly reduced in women with sPTB at < 37 weeks, as well as in those who had PPROM, compared to those who delivered at term. Screening by a combination of maternal risk factors, PAPP-A and PlGF achieved better performance in predicting sPTB at < 37 weeks (AUC, 0.630 vs 0.555; detection rate (DR), 24.8% vs 16.6% at a false-positive rate (FPR) of 10%; P ≤ 0.0001) and PPROM at < 37 weeks (AUC, 0.643 vs 0.558; DR, 28.1% vs 17.0% at a FPR of 10%; P ≤ 0.0001) than using maternal risk factors alone. Both models were successfully applied to the internal validation dataset, with AUCs of 0.628 and 0.650, respectively.

CONCLUSIONS

We demonstrated that low levels of maternal serum PAPP-A and PlGF in the first trimester are associated with increased risks of sPTB and PPROM at < 37 weeks. However, further research is needed to identify additional biomarkers to improve the screening performance of the combined model that includes maternal risk factors, PAPP-A and PlGF before clinical application. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

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.

Life After Amsterdam: Placental Pathology Consensus Recommendations and Beyond

The Amsterdam Placental Workshop Group Consensus Statement on Sampling and Definitions of Placental Lesions has become widely accepted and is increasingly used as the universal language to describe the most common pathologic lesions found in the placenta. This review summarizes the most salient aspects of this seminal publication and the subsequent emerging literature based on Amsterdam definitions and criteria, with emphasis on publications relating to diagnosis, grading, and staging of placental pathologic conditions. We also provide an overview of the recent expert recommendations on the pathologic grading of placenta accreta spectrum, with insights on their clinical context. Finally, we discuss the emerging entity of SARS-CoV2 placentitis.

First trimester HtrA1 maternal plasma level and spontaneous preterm birth

OBJECTIVES

High temperature requirement A1 (HtrA1) is a serine protease detected in maternal plasma and in placental tissues during normal gestation and in various pathological conditions. The purpose of this study was to determine whether the maternal plasma concentration of HtrA1 in first trimester, alone or combined with other maternal factors, can be used to identify women at risk for spontaneous preterm birth (SPTB).

STUDY DESIGN

This is a cohort study on pregnant women at 12 weeks of gestation recruited between 2014 and 2016 and prospectively followed until delivery. One hundred and fifty-nine women were included in the study: 140 women delivered at term and 19 (11.9%) delivered spontaneously preterm. Plasma samples were assessed for HtrA1 by ELISA and data were compared between women which delivered at term with women which delivered preterm. A multiple logistic regression analysis was used to estimate the independent effect of women's characteristics on the probability of a SPTB.

RESULTS

SPTB was significantly associated with log HtrA1 values at 12 weeks of gestation, BMI before pregnancy and physical activity. In particular, the probability of a SPTB increases of 79% for every added unit of log HtrA1, while decreases of 18% for every added unit of BMI. In addition, physical activity was found as an important protective factor. The ROC curve showed that the model had a good accuracy in predicting SPTB, with an AUC equal to 0.83 (95%CI: 0.73-0.91).

CONCLUSIONS

Maternal plasma HtrA1 may be considered a marker of SPTB. In addition, our model indicates two factors that could be modified to reduce the risk of SPTB, i.e. BMI before pregnancy and maternal physical activity.

Analysis of the relationship between placental histopathological aspects of preterm and term birth

OBJECTIVES

This study aims to establish a correlation between placental histopathological and immunohistochemical (IHC) changes and preterm birth with fetal growth restriction (FGR, formerly called intrauterine growth restriction - IUGR).

PATIENTS, MATERIALS, AND METHODS

This prospective study was performed on a group of 30 parturients, with singleton gestation, of which 15 patients gave birth at term, and the other 15 patients gave birth prematurely. After the statistical correlation of the clinical and demographic data with premature birth (PB) and term birth (TB), we performed histological and IHC research on the respective placentae. To observe normal and pathological microscopic placental structures, we used the Hematoxylin-Eosin (HE) and Periodic Acid Schiff-Hematoxylin (PAS-H) classical stainings, but also special immunostaining with anti-cluster of differentiation 34 (CD34) and anti-vascular endothelial growth factor (VEGF) antibodies.

RESULTS

We found a statistically significant difference between the TB∕PB categories and the age of the patients, their antepartum weight, the weight of the newborns, and the placenta according to the sex of the newborn. Histological analysis revealed in the case of TB, small areas of perivillous amyloid deposition, with the significant extension of these areas both intravillous and perivillous in the case of PB. Massive intravillous calcifications, syncytial knots, and intravillous vascular thrombosis were also frequently present in PB. With PAS-H staining were highlighted the intra∕extravillous vascular basement membranes, but especially the massive fibrin deposits rich in glycosaminoglycans. By the IHC technique with the anti-CD34 antibody, we noticed the numerical vascular density, higher in the case of TB, but in the case of PB, there were large areas of placental infarction, with a lack of immunostaining in these areas. Through the anti-VEGF antibody, we observed the presence of signal proteins that determined and stimulated the formation of neoformation vessels in the areas affected by the lack of post-infarction placental vascularization. We observed a highly significant difference between placental vascular density between TB∕PB and newborn weight, sex, or placental weight.

CONCLUSIONS

Any direct proportional link between the clinical maternal-fetal and histological elements yet studied must be considered. Thus, establishing an antepartum risk group can prevent a poor pregnancy outcome.

Proteomic identification of novel plasma biomarkers associated with spontaneous preterm birth in women with preterm labor without infection/inflammation

Objective

We sought to identify plasma biomarkers associated with spontaneous preterm birth (SPTB, delivery within 21 days of sampling) in women with preterm labor (PTL) without intra-amniotic infection/inflammation (IAI) using label-free quantitative proteomic analysis, as well as to elucidate specific protein pathways involved in these cases.

Methods

This was a retrospective cohort study comprising 104 singleton pregnant women with PTL (24–32 weeks) who underwent amniocentesis and demonstrated no evidence of IAI. Analysis of pooled plasma samples collected from SPTB cases and term birth (TB) controls (n = 10 for each group) was performed using label-free quantitative mass spectrometry for proteome profiling in a nested case-control study design. Eight candidate proteins of interest were validated by ELISA-based assay and a clot-based assay in the total cohort.

Results

Ninety-one proteins were differentially expressed (P < 0.05) in plasma samples obtained from SPTB cases, of which 53 (58.2%) were upregulated and 38 (41.8%) were downregulated when compared to TD controls. A validation study confirmed that plasma from women who delivered spontaneously within 21 days of sampling contained significantly higher levels of coagulation factor Ⅴ and lower levels of S100 calcium binding protein A9 (S100A9), especially the former which was independent of baseline variables. The top-ranked pathways related to the 91 differentially expressed proteins were liver-X-receptor/retinoid X receptor (RXR) activation, acute phase response signaling, farnesoid X receptor/RXR activation, coagulation system, and complement system.

Conclusions

Proteomic analyses in this study identified potential novel biomarkers (i.e., coagulation factor V and S100A9) and potential protein pathways in plasma associated with SPTB in the absence of IAI in women with PTL. The present findings provide novel insights into the molecular pathogenesis and therapeutic targets specific for idiopathic SPTB.

In vitro fertilization is associated with placental accelerated villous maturation

OBJECTIVE

Accelerated placental maturation is regarded as a sign of vascular malperfusion and is often interpreted as a compensatory response by the placenta. In vitro embryo culture affects placental development. This study assessed placental maturation in spontaneous conceived and in vitro conceived pregnancies.

METHODS

Retrospective cohort study on a single center between 2014 and 2017. For this study, preterm placentas of singleton pregnancies between 24 and 36 weeks were considered. Routine placental examinations were retrospectively reviewed.

RESULTS

During the considered period, 423 placentas of singleton pregnancies were assessed. Three hundred ninety-six placentas were from spontaneous conception and 20 from in vitro fertilization and embryo transfer (IVF/ET). IVF/ET was significantly associated with accelerated villous maturation (AVM) and distal villous hypoplasia (DVH) (P<0.05).

CONCLUSIONS

Placental AVM and DVH were significantly associated with in vitro fertilization in singleton pregnancies. This result supports the hypothesis that AVM is a compensatory response by the placenta to improve its transport capacity in specific settings such as in vitro fertilization.

Disorders of placental villous maturation are present in one-third of cases with spontaneous preterm labor

OBJECTIVES

Spontaneous preterm labor is an obstetrical syndrome accounting for approximately 65-70% of preterm births, the latter being the most frequent cause of neonatal death and the second most frequent cause of death in children less than five years of age worldwide. The purpose of this study was to determine and compare to uncomplicated pregnancies (1) the frequency of placental disorders of villous maturation in spontaneous preterm labor; (2) the frequency of other placental morphologic characteristics associated with the preterm labor syndrome; and (3) the distribution of these lesions according to gestational age at delivery and their severity.

METHODS

A case-control study of singleton pregnant women was conducted that included (1) uncomplicated pregnancies (controls, n=944) and (2) pregnancies with spontaneous preterm labor (cases, n=438). All placentas underwent histopathologic examination. Patients with chronic maternal diseases (e.g., chronic hypertension, diabetes mellitus, renal disease, thyroid disease, asthma, autoimmune disease, and coagulopathies), fetal malformations, chromosomal abnormalities, multifetal gestation, preeclampsia, eclampsia, preterm prelabor rupture of the fetal membranes, gestational hypertension, gestational diabetes mellitus, and HELLP (hemolysis, elevated liver enzymes and low platelet count) syndrome were excluded from the study.

RESULTS

Compared to the controls, the most prevalent placental lesions among the cases were the disorders of villous maturation (31.8% [106/333] including delayed villous maturation 18.6% [62/333] vs. 1.4% [6/442], q<0.0001, prevalence ratio 13.7; and accelerated villous maturation 13.2% [44/333] vs. 0% [0/442], q<0.001). Other lesions in decreasing order of prevalence included hypercapillarized villi (15.6% [68/435] vs. 3.5% [33/938], q<0.001, prevalence ratio 4.4); nucleated red blood cells (1.1% [5/437] vs. 0% [0/938], q<0.01); chronic inflammatory lesions (47.9% [210/438] vs. 29.9% [282/944], q<0.0001, prevalence ratio 1.6); fetal inflammatory response (30.1% [132/438] vs. 23.2% [219/944], q<0.05, prevalence ratio 1.3); maternal inflammatory response (45.5% [195/438] vs. 36.1% [341/944], q<0.01, prevalence ratio 1.2); and maternal vascular malperfusion (44.5% [195/438] vs. 35.7% [337/944], q<0.01, prevalence ratio 1.2). Accelerated villous maturation did not show gestational age-dependent association with any other placental lesion while delayed villous maturation showed a gestational age-dependent association with acute placental inflammation (q-value=0.005).

CONCLUSIONS

Disorders of villous maturation are present in nearly one-third of the cases of spontaneous preterm labor.

Methodology for Biometrical Analysis of the Placenta: Feasibility and Reproducibility

The role of a healthy placenta as the interface between mother and fetus, which regulates the intrauterine environment and affects fetal and pregnancy outcomes, points to placental examination as a potentially useful diagnostic tool. Placental macroscopic and microscopic patterns are routinely evaluated when pregnancy complications occur. Moreover, placental measures particularly the ratio between fetal and placental weight have been reported to correlate with maternal characteristics, such as BMI as well as with birth-weight and fetal gender. Our pilot study evaluates the feasibility of the placental measures' reproducibility intra-operators. We enrolled 50 consecutive singleton pregnancies including physiological pregnancies and any pre-existing maternal disease or maternal and fetal complication. We conducted a macroscopic analysis of fetal adnexa with four different operators assessing pathological findings or other abnormalities. Intra-class correlation coefficient (ICC) and Cohen and Fleiss kappa coefficient were used to assess the degree of consistency between operators. The results of our study show that the placental morphometric analysis is a reproducible method.

Male fetal sex affects uteroplacental angiogenesis in growth restriction mouse model†

Abnormally increased angiotensin II activity related to maternal angiotensinogen (AGT) genetic variants, or aberrant receptor activation, is associated with small-for-gestational-age babies and abnormal uterine spiral artery remodeling in humans. Our group studies a murine AGT gene titration transgenic (TG; 3-copies of the AGT gene) model, which has a 20% increase in AGT expression mimicking a common human AGT genetic variant (A[-6]G) associated with intrauterine growth restriction (IUGR) and spiral artery pathology. We hypothesized that aberrant maternal AGT expression impacts pregnancy-induced uterine spiral artery angiogenesis in this mouse model leading to IUGR. We controlled for fetal sex and fetal genotype (e.g., only 2-copy wild-type [WT] progeny from WT and TG dams were included). Uteroplacental samples from WT and TG dams from early (days 6.5 and 8.5), mid (d12.5), and late (d16.5) gestation were studied to assess uterine natural killer (uNK) cell phenotypes, decidual metrial triangle angiogenic factors, placental growth and capillary density, placental transcriptomics, and placental nutrient transport. Spiral artery architecture was evaluated at day 16.5 by contrast-perfused three-dimensional microcomputed tomography (3D microCT). Our results suggest that uteroplacental angiogenesis is significantly reduced in TG dams at day 16.5. Males from TG dams are associated with significantly reduced uteroplacental angiogenesis from early to late gestation compared with their female littermates and WT controls. Angiogenesis was not different between fetal sexes from WT dams. We conclude that male fetal sex compounds the pathologic impact of maternal genotype in this mouse model of growth restriction.

Identifying potential biomarkers related to pre-term delivery by proteomic analysis of amniotic fluid

We sought to identify biomarkers in the amniotic fluid (AF) and specific signaling pathways related to spontaneous preterm delivery (SPTD, < 34 weeks) in women with preterm labor (PTL) without intra-uterine infection/inflammation (IUI). This was a retrospective cohort study of a total of 139 PTL women with singleton gestation (24 + 0 to 32 + 6 weeks) who underwent amniocentesis and who displayed no evidence of IUI. A nested case-control was conducted using pooled AF samples (n = 20) analyzed via label-free liquid chromatography-tandem mass spectrometry. In the total cohort, an ELISA validation study was performed for seven candidate proteins of interest. Proteomic analysis identified 77 differentially expressed proteins (DEPs, P < 0.05) in the AF from SPTD cases compared to term delivery controls. ELISA validation confirmed that women who had an SPTD before 34 weeks had significantly independently lower levels of VEGFR-1 and higher levels of lipocalin-2 and the Fc fragment of IgG binding protein in the AF. Five principle pathways associated with the 77 DEPs were identified, including glycolysis, gluconeogenesis, and iron homeostasis. The proteomic analysis data of AFs from women with PTL identified several novel biomarkers and specific protein pathways related to SPTD in the absence of IUI.

Gross morphologic appearance of chorionic villi and the risk of chromosomal abnormalities

Chromosomal abnormalities are associated with changes in complex aspects of chorionic villi histomorphology. This study used a simple scoring system to evaluate the association between atypical gross morphology and abnormal chromosomal testing on chorionic villus sampling (CVS). This retrospective cohort study included singleton pregnancies that underwent CVS at a single institution from 2006-2017. The degree of budding, branching, and vascularity (BBV) was scored from 0 to 3 for each CVS specimen, and individual scores were summed to calculate a composite BBV score. Scores were categorized into typical or atypical based on the cohort's distribution. The primary predictor was atypical BBV score, and the primary outcome was chromosomal abnormality. Fisher's exact test compared proportions, and logistic regression generated odds ratios. Among 1171 CVS specimens, 28% had chromosomal abnormalities. The chromosomally abnormal group had a higher rate of atypical BBV score than the normal group (7.3% vs 3.7%, P=0.009), a finding that remained statistically significant after controlling for maternal age, gestational age, and mode of CVS (aOR 2.2, 95% CI 1.24-3.82). Atypical chorionic villus morphology is associated with chromosomal abnormalities. This scoring system is simple, rapid, and easy to perform at the time of routine diagnosis.

Impact of intramural non-cavity-distorting leiomyoma on placental histopathology and perinatal outcome in singleton live births resulting from in vitro fertilization treatment

PURPOSE

To evaluate the effect of non-cavity-distorting intramural leiomyomas on the placental histopathology pattern and perinatal outcome in singleton live births resulting from in vitro fertilization treatment.

METHODS

The study population included all singleton live births following in vitro fertilization treatment with autologous oocytes during the period from 2009 to 2017. Primary outcomes included anatomical, inflammation, vascular malperfusion, and villous maturation placental features. Secondary outcomes included fetal, maternal, delivery, and perinatal complications.

RESULTS

A total of 1119 live births were included in the final analysis and were allocated to the group of pregnancies with non-cavity-distorting intramural myomas (n = 101) and without myomas (n = 1018). After the adjustment for confounding factors, the non-cavity-distorting intramural myomas were found to be significantly associated with assisted placental delivery (OR 2.4; 95% CI 1.5-3.9), furcate cord insertion (OR 3.6; 95% CI 1.4-9.3), circumvallate membranes insertion (OR 5.2; 95% CI 1.4-19.3), chronic deciduitis (OR 8.2; 95% CI 1.6-42.2), focal intramural fibrin deposition (OR 25.1; 95% CI 2.1-306.2), subchorionic thrombi (OR 3.6; 95% CI 1.7-7.6), maternal vasculopathy (OR 2.5; 95% CI 1.2-5.5), and chorangioma (OR 5.9; 95% CI 1.4-25.2) as well as with the failure of labor progress (OR 2.4; 95% CI 1.3-4.4) and induction (OR 3.2; 95% CI 1.2-9.0).

CONCLUSION

Intramural non-cavity-distorting myomas have a significant impact on the placental histopathology with a higher incidence of dysfunctional labor.

Increased incidence of hypertensive disorders of pregnancy in women with a history of spontaneous preterm birth: A longitudinal linked national cohort study

OBJECTIVE

Determine the risk of hypertensive disorders of pregnancy (HD) in women with a history of spontaneous preterm birth (SPTB).

STUDY DESIGN

Longitudinal linked national cohort study within the Dutch Perinatal Registry (1999-2009) on linked data among 349,291 women with a first and second singleton pregnancy in the Netherlands.

MAIN OUTCOME MEASURES

The incidence of HD, small for gestational age (SGA) and placental abruption in the second pregnancy.

RESULTS

Out of 349,291 women with a singleton first pregnancy, 19,991 (5.7%) had a SPTB. The incidence of HD in the second pregnancy was 8.1% in women with a previous SPTB, as compared to 5.6% in women with a previous term birth (aOR 1.49 (CI 1.41-1.57)). Also after excluding HD, SGA and/or placental abruption in the first pregnancy, women with a history of SPTB had a higher risk of HD in their second pregnancy compared to women with a previous term birth (4.6% versus 2.7%, aOR 1.77 (CI 1.64-191)). Similarly, the incidence of SGA and placental abruption was higher in the second pregnancy in women with a history of SPTB compared to term birth in the first pregnancy.

CONCLUSIONS

Women with a history of SPTB are at elevated risk of HD in the subsequent pregnancy. These results support shared pathophysiology between SPTB and HD.

The effect of mother's β-thalassemia minor on placental histology and neonatal outcomes

Objective: β-thalassemia is a prevalent disease in Iran. The adverse effects of anemia on placental and neonatal outcomes have previously been shown. Women require additional iron during pregnancy and the anemia of women with β-thalassemia may adversely affect the neonatal outcome and increase placental abnormalities. In this study, we compared the placental histology and neonatal outcomes among pregnant women with and without β-thalassemia.Material and methods: In this population-based cross-sectional study, 144 pregnant women with β-thalassemia minor (case group) were compared to 142 women without β-thalassemia (control group). Women with singleton pregnancies over 20 weeks of gestation without pregnancy complications, anemia, collagen vascular diseases, or other hemoglobinopathies, all referred to hospitals affiliated to Shiraz University of Medical Sciences from March 2014 to February 2016, were included and maternal and neonatal data were extracted from medical records. After child birth, the placenta was evaluated for macroscopic and microscopic changes.Results: The frequency of LBW was significantly higher in the case group than that in the control group (19.7 vs. 9.7%, respectively) (p = .019). Six in the case group had gross abnormalities of placenta, while none in the control group (p = .03) and the case group had a higher frequency of chorangiosis, calcification, syncytial knot, and umbilical cord position (p < .05).Conclusion: As β-thalassemia increases the chance of placental abnormalities, it is recommended to pay more attention to patients with β-thalassemia, especially during pregnancy, to prevent placental and neonatal adverse outcomes.

Disorders of placental villous maturation in fetal death

Objective The aims of this study were to ascertain the frequency of disorders of villous maturation in fetal death and to also delineate other placental histopathologic lesions in fetal death. Methods This was a retrospective observational cohort study of fetal deaths occurring among women between January 2004 and January 2016 at Hutzel Women's Hospital, Detroit, MI, USA. Cases comprised fetuses with death beyond 20 weeks' gestation. Fetal deaths with congenital anomalies and multiple gestations were excluded. Controls included pregnant women without medical/obstetrical complications and delivered singleton, term (37-42 weeks) neonate with 5-min Apgar score ≥7 and birthweight between the 10th and 90th percentiles. Results Ninety-two percent (132/143) of placentas with fetal death showed placental histologic lesions. Fetal deaths were associated with (1) higher frequency of disorders of villous maturation [44.0% (64/143) vs. 1.0% (4/405), P < 0.0001, prevalence ratio, 44.6; delayed villous maturation, 22% (31/143); accelerated villous maturation, 20% (28/143); and maturation arrest, 4% (5/143)]; (2) higher frequency of maternal vascular malperfusion lesions [75.5% (108/143) vs. 35.7% (337/944), P < 0.0001, prevalence ratio, 2.1] and fetal vascular malperfusion lesions [88.1% (126/143) vs. 19.7% (186/944), P < 0.0001, prevalence ratio, 4.5]; (3) higher frequency of placental histologic patterns suggestive of hypoxia [59.0% (85/143) vs. 9.3% (82/942), P < 0.0001, prevalence ratio, 6.8]; and (4) higher frequency of chronic inflammatory lesions [53.1% (76/143) vs. 29.9% (282/944), P < 0.001, prevalence ratio 1.8]. Conclusion This study demonstrates that placentas of women with fetal death were 44 times more likely to present disorders of villous maturation compared to placentas of those with normal pregnancy. This suggests that the burden of placental disorders of villous maturation lesions is substantial.

Unique transcriptomic landscapes identified in idiopathic spontaneous and infection related preterm births compared to normal term births

Preterm birth (PTB) is leading contributor to infant death in the United States and globally, yet the underlying mechanistic causes are not well understood. Histopathological studies of preterm birth suggest advanced villous maturity may have a role in idiopathic spontaneous preterm birth (isPTB). To better understand pathological and molecular basis of isPTB, we compared placental villous transcriptomes from carefully phenotyped cohorts of PTB due to infection or isPTB between 28–36 weeks gestation and healthy term placentas. Transcriptomic analyses revealed a unique expression signature for isPTB distinct from the age-matched controls that were delivered prematurely due to infection. This signature included the upregulation of three IGF binding proteins (IGFBP1, IGFBP2, and IGFBP6), supporting a role for aberrant IGF signaling in isPTB. However, within the isPTB expression signature, we detected secondary signature of inflammatory markers including TNC, C3, CFH, and C1R, which have been associated with placental maturity. In contrast, the expression signature of the gestational age-matched infected samples included upregulation of proliferative genes along with cell cycling and mitosis pathways. Together, these data suggest an isPTB molecular signature of placental hypermaturity, likely contributing to the premature activation of inflammatory pathways associated with birth and providing a molecular basis for idiopathic spontaneous birth.

Maternal vascular malformation in the placenta is an indicator for fetal growth restriction irrespective of neonatal birthweight

INTRODUCTION

To study the association between placental pathology and neonatal birthweight and outcomes, and whether a combination of first trimester biomarkers and fetal growth velocity can predict placental lesions.

METHODS

The presence of maternal vascular malperfusion (MVM) lesions (Amsterdam criteria) was recorded in a retrospective cohort of singleton pregnancies in the Maastricht University Medical Centre, 2011-2018. First trimester maternal characteristics and PAPP-A, PlGF and sFlt-1 levels were collected. Fetal growth velocities were calculated (mm/week) from 20 to 32 weeks for abdominal circumference, biparietal diameter, head circumference and femur length. Data were compared between neonates with 'small for gestational age' (SGA < p10) and different categories of 'appropriate for gestational age (AGA)': AGAp10-30, AGAp30-50 and AGA > p50 (reference), using one-way ANOVA and post hoc test.

RESULTS

There were significantly more MVM lesions in the SGA group (94.6% p < .0001), but also in the AGAp10-30 (67.3% p < .0001) and AGAp30-50 (41.6% p = 0.002), compared to the reference AGA group (19.3%). The prediction of MVM for a 20% false-positive rate, with maternal characteristics was25.2%. The addition of birthweight percentile gave a prediction of 51.7% for MVM. However adding placental biomarkers and fetal growth velocities (instead of birthweight percentile) to the maternal characteristics, gave a prediction of 81.8% (PPV 49.5%, NPV 53.7%).

DISCUSSION

Placental MVM lesions correlated inversely with birthweight even in AGA neonates, and was associated with slower fetal growth and more adverse outcome in SGA neonates. A combination of first trimester biomarkers and fetal growth velocity had good prediction of placental MVM lesions, as an indicator of fetal growth restriction irrespective of neonatal weight.

Mechanisms of death in structurally normal stillbirths

Objectives To investigate mechanisms of in utero death in normally formed fetuses by measuring amniotic fluid (AF) biomarkers for hypoxia (erythropoietin [EPO]), myocardial damage (cardiac troponin I [cTnI]) and brain injury (glial fibrillary acidic protein [GFAP]), correlated with risk factors for fetal death and placental histopathology. Methods This retrospective, observational cohort study included intrauterine deaths with transabdominal amniocentesis prior to induction of labor. Women with a normal pregnancy and an indicated amniocentesis at term were randomly selected as controls. AF was assayed for EPO, cTnI and GFAP using commercial immunoassays. Placental histopathology was reviewed, and CD15-immunohistochemistry was used. Analyte concentrations >90th centile for controls were considered "raised". Raised AF EPO, AF cTnI and AF GFAP concentrations were considered evidence of hypoxia, myocardial and brain injury, respectively. Results There were 60 cases and 60 controls. Hypoxia was present in 88% (53/60), myocardial damage in 70% (42/60) and brain injury in 45% (27/60) of fetal deaths. Hypoxic fetuses had evidence of myocardial injury, brain injury or both in 77% (41/53), 49% (26/53) and 13% (7/53) of cases, respectively. Histopathological evidence for placental dysfunction was found in 74% (43/58) of these cases. Conclusion Hypoxia, secondary to placental dysfunction, was found to be the mechanism of death in the majority of fetal deaths among structurally normal fetuses. Ninety-one percent of hypoxic fetal deaths sustained brain, myocardial or both brain and myocardial injuries in utero. Hypoxic myocardial injury was an attributable mechanism of death in 70% of the cases. Non-hypoxic cases may be caused by cardiac arrhythmia secondary to a cardiac conduction defect.

Placental villous hypermaturation is associated with improved neonatal outcomes

INTRODUCTION

Accelerated placental maturation is considered a sign of maternal vascular malperfusion, and is often interpreted as an adaptive, compensatory response by the placenta. We tested this interpretation by comparing outcomes in pregnancies with and without accelerated maturation.

METHODS

Using data from the National Collaborative Perinatal Project, we categorized preterm placentas (24-34 weeks, inclusive; 2525 births) by whether they showed placental villous hypermaturation (PVH), i.e., had the appearance of a placenta of 37 weeks or over upon microscopic examination. We assessed whether PVH was associated with maternal race, maternal BMI, fetal sex, type of preterm birth, preeclampsia, signs of infection or inflammation or placental abruption. We also assessed whether placentas showing PVH were associated with improved outcomes in terms of survival, Apgar score, or oxygen use.

RESULTS

PVH was more common in preeclamptic pregnancies and less common in pregnancies complicated by placental abruption or showing signs of placental infection or inflammation. Adjusting for potentially confounding factors, PVH was associated with reduced odds of fetal death, death between birth and 120 days of age, low Apgar scores and oxygen use. PVH was also associated with higher birthweights for gestational age. When correcting for the effect of birthweight, the association between PVH and reduced fetal and neonatal death remained significant.

DISCUSSION

Accelerated placental maturation, as manifested by PVH, is associated with improved outcomes. Our work therefore supports the hypothesis that accelerated maturation is a compensatory response by the placenta to improve its transport capacity in specific pregnancy complications.

Association between maternal/newborn genetic variants, placental pathology and spontaneous preterm birth risk: a Romanian population-based study

Objective: The objective of this study was to determine the association between maternal/newborn single-nucleotide polymorphisms (SNPs) in three candidate genes, placental pathology and the risk of spontaneous preterm birth (SPTB) in a Romanian population.Methods: We performed a prospective case-control study in a tertiary maternity in Romania, including 79 mother-newborn pairs with SPTB and 81 mother-newborn pairs with term delivery. Using real-time Polymerase Chain Reaction (PCR), three SNPs rs8192282 A > G, rs2277698 C > T and rs34003 A > C located on interleukin 6 receptor (IL6R), tissue inhibitor of matrix metalloproteinase-2 (TIMP2) and fibroblast growth factor 1 (FGF1) genes were assessed. The minor allele and genotype frequencies were compared between groups. Multilocus genetic association analyses were performed. From pathology reports, the morphological and histopathological examination of the placentas were extracted.Results: The rs34003 C/C genotype frequency in newborns FGF1 gene was significantly higher in the spontaneous preterm birth (SPTB) group compared to the control group (p = .045). In single-locus analyses, C/C genotype was associated with an increased risk of spontaneous preterm birth (OR = 2.59, 95%CI: 1.02-6.58). Additionally, this homozygote genotype was correlated with the presence of placental pathology, especially with the inflammatory and vascular lesions (p < .01). The prediction model based on rs34003 C/C genotype - placental pathology joint influence had a statistically significant regression coefficient (p < .01, OR = 7.76, 95%CI: 4.03-14.93). Single nucleotide polymorphisms related to IL6R gene in maternal samples and FGF1 gene in newborns were associated with spontaneous preterm delivery in multilocus genetic association analyses (p = .028, OR of 2.375).Conclusions: Our results indicate that rs34003 C/C genotype in newborns FGF1gene is correlated with the occurrence of placental pathological lesions and with an increased SPTB risk. The association of two SNPs in maternal and fetal genes doubled the risk of spontaneous preterm birth in our population.

The problem with using the birthweight:placental weight ratio as a measure of placental efficiency

INTRODUCTION

The ratio of birthweight to placental weight (BW:PW) is often used as a measure of placental efficiency in humans and animals. However, ratios have properties that are known to lead to spurious results. An alternative approach is the use of residuals from regression, which reflect whether birthweight is higher or lower than expected for a given placental weight, given the population pattern. We hypothesized that biologically meaningful measures of placental efficiency would differ between placentas with and without pathology, and between adverse and normal perinatal and postnatal outcomes.

METHODS

We examined associations between measures of placental efficiency (BW:PW ratio or residuals) and placental pathology, Apgar scores and infant death using National Collaborative Perinatal Project data (4645 preterm births and 28497 term births).

RESULTS

BW:PW ratios and residuals were significantly lower in placentas showing pathologies including signs of large infarcts or hemorrhage, although many of these differences were small. Low BW:PW ratios and residuals were also associated with low Apgar scores and increased risk of postnatal death. Whereas residuals were lower in term placentas that appeared immature by microscopic examination, the opposite was true for BW:PW ratios.

CONCLUSION

The BW:PW ratio produced an artefact whereby histologically less mature placentas at term appeared to be more "efficient" than mature placentas, illustrating a known problem with the use of ratios. For other traits, residuals generally showed differences between placentas with and without pathology that were as great as those seen with BW:PW ratios, and often showed stronger associations with adverse outcomes.

What is the most suitable MR signal index for quantitative evaluation of placental function using Half-Fourier acquisition single-shot turbo spin-echo compared with T2-relaxation time?

Background Half-Fourier acquisition single-shot turbo spin-echo (HASTE) imaging is now widely used for placental and fetal imaging because of its rapidity and low sensitivity to fetal movement. If placental dysfunction is also predicted by quantitative value obtained from HASTE image, then it might be beneficial for evaluating placental wellbeing. Purpose To ascertain the most suitable magnetic resonance (MR) signal indexes reflecting placental function using HASTE imaging. Material and Methods This retrospective study included 37 consequent patients who had given informed consent to MR imaging (MRI) examinations. All had undergone MRI examinations between February 2014 and June 2015. First, the correlation between T2-relaxation time of normal placenta and gestational age (GA) was examined. Second, correlation between signal intensity ratios (SIRs) using HASTE imaging and placental T2-relaxation time were assessed. The SIRs were calculated using placental signal intensity (SI) relative to the SI of the amniotic fluid, fetal ocular globes, gastric fluid, bladder, maternal psoas major muscles, and abdominal subcutaneous adipose tissue. Results Among the 37 patients, the correlation between T2-relaxation time of the 25 normal placentas and GA showed a moderately strong correlation (Spearman rho = -0.447, P = 0.0250). The most significant correlation with placental T2-relaxation time was observed with the placental SIR relative to the maternal psoas major muscles (SIR_{pl./psoas muscle}) (Spearman rho = -0.531, P = 0.0007). Conclusion This study revealed that SIR_{pl./psoas muscle} showed the best correlation to placental T2-relaxation time. Results show that SIR_{pl./psoas muscle} might be optimal as a clinically available quantitative index of placental function.

Calciprotein particles as potential etiologic agents of idiopathic preterm birth

Preterm birth (PTB) is a leading cause of neonatal morbidity and mortality and is often preceded by preterm premature rupture of the membranes (PPROM) without an identifiable cause. Pathological calcification, the deposition of hydroxyapatite (HA) in nonskeletal tissues, has been implicated in degenerative diseases including atherosclerosis and aneurism rupture. Among pathogenic mechanisms, the aberrant aggregation of HA into calciprotein particles (CPPs) and the HA-induced differentiation of mesenchymal cells into osteoblasts (ectopic osteogenesis) have been implicated. We explored the hypothesis that CPPs form in human amniotic fluid (AF), deposit in fetal membranes, and are linked mechanistically to pathogenic pathways favoring PTB. We demonstrated that fetal membranes from women with idiopathic PPROM frequently show evidence of ectopic calcification and expression of osteoblastic differentiation markers. Concentrations of fetuin-A, an endogenous inhibitor of ectopic calcification, were decreased in AF of idiopathic PPROM cases, which reflected their reduced functional capacity to inhibit calcification. Using long-term cultures of sterile AF, we demonstrated coaggregation of HA with endogenous proteins, including fetuin-A. The fetuin-HA aggregates exhibited progressive growth in vitro in a pattern similar to CPPs. When applied to amniochorion explants, AF-derived CPPs induced structural and functional pathological effects recapitulating those noted for PPROM. Our results demonstrate that disruption of protein-mineral homeostasis in AF stimulates the formation and deposition of CPPs, which may represent etiologic agents of idiopathic PPROM. Therapeutic or dietary interventions aimed at maintaining the balance between endogenous HA formation and fetuin reserve in pregnant women may therefore have a role in preventing PTB.

Maternal exercise during pregnancy reduces the risk of preterm birth through the mediating role of placenta

OBJECTIVE

The extent of research on maternal exercise during pregnancy and the risk of preterm birth (PTB) have grown substantially, but conclusions still remained controversial. Thus, this study aims to examine the relationship of maternal exercise during pregnancy and PTB and explore whether placenta mediates their relationship.

STUDY DESIGN

We investigated 849 pregnant women delivering PTB newborns (cases) and 1306 delivering full-term appropriate for gestational age newborns (controls) in this case-control study. Information concerning maternal exercise during pregnancy, sociodemographics and obstetric characteristics were collected at Women and Children's Hospitals of Shenzhen and Foshan in Guangdong, China. A series of logistic and linear regressions were used to examine the relationships of maternal exercise during pregnancy, placenta, and PTB.

RESULTS

After adjusting for the potential confounders, maternal exercise frequency and duration during pregnancy were negatively associated with PTB. Moreover, compared with mother taking no exercise during pregnancy, those taking exercise lowered the risk of PTB except those taking low/medium frequency and short duration exercise, and their adjusted ORs ranged from 0.43 to 0.65. Furthermore, mediation analysis illustrated that placental weight partially mediated 65.20% of the effects of maternal exercise frequency on PTB, as well as 41.98% of the association between maternal exercise duration and PTB.

CONCLUSIONS

Maternal exercise during pregnancy is beneficial for lowering the risk of PTB, especially when taking appropriate and enough exercise. Placenta weight may partially mediate the association between maternal exercise during pregnancy and PTB.

Placental histology in spontaneous and indicated preterm birth: A case control study

INTRODUCTION

Placental pathology is an important contributor in preterm birth, both spontaneous and indicated. The aim of this study was to describe and compare placental histological features of spontaneous preterm birth versus indicated preterm birth.

METHODS

A case control study was performed at the University Medical Center Utrecht. Women with spontaneous or indicated preterm birth (17-37 weeks of gestation) delivered in 2009 were included. Women with a pregnancy complicated by congenital and/or chromosomal abnormalities were excluded. Placentas were systematically examined by an expert pathologist blinded for pregnancy outcome, except for gestational age. Placental histological abnormalities were classified into infectious inflammatory lesions and maternal vascular malperfusion lesions and compared between spontaneous and indicated preterm birth. Analysis was stratified for immature (17-23⁺⁶ weeks), extremely (24-27⁺⁶ weeks), very (28-31⁺⁶ weeks) and moderate/late (32-36⁺⁶ weeks) preterm birth.

RESULTS

We included 233 women, 121 women with spontaneous preterm birth and 112 women with indicated preterm birth. Among women with spontaneous extremely preterm birth, higher rates of severe chorioamnionitis were found (56.0% vs. 0%). Furthermore, a shift from infectious-inflammatory lesions to maternal vascular malperfusion lesions was seen after 28 weeks; in women with spontaneous very and moderate/late preterm birth, maternal vascular malperfusion lesions were the main finding (46.8% and 47.7% respectively). In women with indicated preterm birth, maternal vascular malperfusion lesions were most often contributing through all gestational age categories.

CONCLUSION

Maternal vascular malperfusion lesions are most frequent in both spontaneous and indicated very and moderate/late preterm birth. In spontaneous extreme preterm birth chorioamnionitis is the main finding.

Sampling and Definitions of Placental Lesions: Amsterdam Placental Workshop Group Consensus Statement

CONTEXT

-The value of placental examination in investigations of adverse pregnancy outcomes may be compromised by sampling and definition differences between laboratories.

OBJECTIVE

-To establish an agreed-upon protocol for sampling the placenta, and for diagnostic criteria for placental lesions. Recommendations would cover reporting placentas in tertiary centers as well as in community hospitals and district general hospitals, and are also relevant to the scientific research community.

DATA SOURCES

-Areas of controversy or uncertainty were explored prior to a 1-day meeting where placental and perinatal pathologists, and maternal-fetal medicine specialists discussed available evidence and subsequently reached consensus where possible.

CONCLUSIONS

-The group agreed on sets of uniform sampling criteria, placental gross descriptors, pathologic terminologies, and diagnostic criteria. The terminology and microscopic descriptions for maternal vascular malperfusion, fetal vascular malperfusion, delayed villous maturation, patterns of ascending intrauterine infection, and villitis of unknown etiology were agreed upon. Topics requiring further discussion were highlighted. Ongoing developments in our understanding of the pathology of the placenta, scientific bases of the maternofetoplacental triad, and evolution of the clinical significance of defined lesions may necessitate further refinements of these consensus guidelines. The proposed structure will assist in international comparability of clinicopathologic and scientific studies and assist in refining the significance of lesions associated with adverse pregnancy and later health outcomes.

Systemic and placental α-klotho: Effects of preeclampsia in the last trimester of gestation

INTRODUCTION

α-klotho is an anti-aging protein, potentially important in preeclampsia (PE). Produced by kidney, brain and placenta, and by mRNA splicing is both a full-length membrane-bound and a truncated soluble protein in the circulation. The membrane-bound protein is an obligate co-receptor for fibroblast growth factor 23 (FGF23) and its action on receptor (FGFR), but ADAM proteinases also cause its shedding. The aims of this study were to investigate levels of maternal plasma, placental, and fetal membrane α-Klotho and their association with placental accelerated villous maturation (AVM) in PE. In addition, placental and membrane levels of ADAM17 and FGFR were measured in the same patients.

METHODS

Maternal blood, placenta and fetal membranes from 61 women (31 with PE and 30 controls) between 32 and 40 weeks gestation were collected. Plasma α-klotho was measured by ELISA, and quantitative immunohistochemistry used for α-klotho, ADAM17 and FGFR1 in tissues. Placental AVM was histologically assessed.

RESULTS

Maternal plasma levels of α-Klotho were higher in PE compared to controls (p = 0.01) and patients with the highest levels had significantly less AVM (p = 0.03). α-Klotho, ADAM17, and FGFR were all present in syncytiotrophoblast and cytotrophoblast of membranes. Between 32 and 40 weeks gestation, all placental levels decreased in controls respectively (p = 0.04, p = 0.004, p = 0.05), but not in PE. Fetal membrane levels were unchanged.

DISCUSSION

Maternal plasma α-Klotho was increased in PE and its levels associated with reduced placental AVM. Changes in placental α-Klotho, ADAM17, and FGFR suggest their involvement in the pathophysiology of PE.

Is evaluation of placenta with real-time sonoelastography during the second trimester of pregnancy an effective method for the assessment of spontaneous preterm birth risk?

PURPOSE

The aim of this study is to investigate the effectiveness of placental strain ratio (SR) values measured by real-time sonoelastography (SE) in the second trimester in the prediction of spontaneous preterm birth (sPTB).

METHODS

This study included 70 pregnant women who applied to our clinic for routine second-trimester screening. Placental SR measurements were performed with the SE method. Two different SR measurements were performed by taking two different tissues as references. The SR value measured when taking the rectus abdominis muscle as a reference was termed the muscle-to-placenta strain ratio (MPSR), while the SR value measured when taking subcutaneous tissue as a reference was termed the fat-to-placenta strain ratio (FPSR). Women whose gestational age at birth was less than 37 weeks 0 days were accepted as sPTB. The association between gestational age at birth and MPSR and FPSR was investigated. Receiver operating characteristics analysis was used to calculate the sensitivity and specificity of the elastographic outcomes.

RESULTS

There was a low-level negative correlation between MPSR and gestational age at birth (r=-0.300, P=.012) and there was a moderate-level negative correlation between FPSR and gestational age at birth (r=-0.513, P<.001). The multivariate linear regression analysis showed that the FPSR (β=0.609, P=.002) was the significant predictor for the sPTB.

CONCLUSIONS

Our data indicate that the FPSR value measured with real-time SE in the second trimester of pregnancy may be effective in the prediction of sPTB.

Placental function assessed visually using half-Fourier acquisition single-shot turbo spin-echo (HASTE) magnetic resonance imaging

INTRODUCTION

To investigate a simple visual assessment method of placental function using half-Fourier acquisition single-shot turbo spin-echo (HASTE) magnetic resonance imaging (MRI).

METHODS

The institutional review board approved this retrospective study of fetal MRI in 48 singleton pregnant women for whom placentas had undergone clinical pathological examinations. Two readers independently assessed the placentas using the HASTE scoring system, particularly emphasizing the visualization of the regular two-tone pattern inside and signal intensity (SI) of placental parenchyma referring to SI of the fetal kidney and liver. After categorization using the HASTE scoring system, the associations between the scores and the presence of pathologically proven placental insufficiency or of low birth weight less than the tenth percentile were examined using chi-square tests. The associations between the HASTE scores and the MRI findings previously reported to suggest placental insufficiency, such as placental thickness and placenta to amniotic fluid SI ratio, were also examined using Student t-tests.

RESULTS

The HASTE scores were associated significantly with the presence of pathologically proven placental insufficiency (P = .003 for reader 1; P = .04 reader 2) and birth weight less than the tenth percentile (P = .005 for reader 1; P = .003 for reader 2). The HASTE scores were associated significantly with the placenta thickness (P < .0001 for both readers) and the placenta to the amniotic fluid SI ratio (P < .0001 for both readers).

DISCUSSION

The HASTE scoring system is feasible for use in clinical assessment of placental function and for diagnosing placental insufficiency.

Type 1, type 2 and gestational diabetes mellitus differentially impact placental pathologic characteristics of uteroplacental malperfusion

INTRODUCTION

During a pregnancy complicated by diabetes, the placenta undergoes a number of functional and structural pathologic changes. However, differences across studies may reflect pathophysiologic differences of diabetes types under investigation.

METHODS

We examined placental pathology from women ages 18-40 years with self-identified race/ethnicity; singleton, live births; and type 1 (T1DM; n = 36), type 2 (T2DM; n = 37), or gestational diabetes mellitus (GDM; n = 126). Clinical data were abstracted from medical records. Placental diagnoses were independently re-reviewed by a perinatal pathologist. Multivariable analyses adjusting for race, gestational weight gain, gestational age, and systolic blood pressure were conducted.

RESULTS

Women with T1DM compared with either T2DM or GDM had higher gestational weight gain (mean ± SD, T1DM vs. T2DM: 28.5 ± 12.4 vs. 20.5 ± 13.4 kg, p = 0.03; or GDM: 21.3 ± 12.7 kg, p = 0.009) and insulin use (T2DM: 100.0% vs. 85.3%, p = 0.02; or GDM: 4.0%, p < 0.001). Women with T1DM compared with either T2DM or GDM also had a similarly lower prevalence of placental infarcts in univariate analyses; however, these findings did not remain significant after multivariable adjustment. Also, placentas from women with T2DM compared to GDM had higher rates of decidual vasculopathy when excluding women with preeclampsia (10.3 vs. 1.6%, p = 0.049) and diffuse chorangiosis (62.2 vs. 32.5%, p < 0.001) but a lower rate of villous immaturity (10.8 vs. 90.5%, p = 0.007) after full adjustment.

DISCUSSION

Placental vasculopathic abnormalities differ by maternal diabetes type, potentially reflecting underlying pathophysiologic mechanisms. Further research on placental pathology and metabolic derangements is warranted.

Do Placental Histopathologic Characteristics Differ with Gestational Ages in Preterm and Term Deliveries?

The study aim is to evaluate the placental histopathological characteristics and maternal risk factors in preterm and term births according to their weeks of gestation. We designed a prospective study involving a patient population (n = 355) composed of pregnant women who delivered preterm (n = 216) and term neonates (n = 139). The preterm births were divided into three groups as extremely (n = 22), moderate (n = 96) and late preterm (n = 98) births. The statistical analyses were performed using SPSS version 15 software. There was significant difference regarding maternal vascular underperfusion and inflammation in the extremely preterm group compared with the other groups (P = 0.001), but fetal vascular obstruction and villitis of unknown etiology were not found significantly different. According to our study results, the careful examination of the placenta of premature babies, particularly those of extremely preterm births, should be part of routine obstetrical management to determine the causes of preterm birth.

The shared pathoetiological effects of particulate air pollution and the social environment on fetal-placental development

Exposure to particulate air pollution and socioeconomic risk factors are shown to be independently associated with adverse pregnancy outcomes; however, their confounding relationship is an epidemiological challenge that requires understanding of their shared etiologic pathways affecting fetal-placental development. The purpose of this paper is to explore the etiological mechanisms associated with exposure to particulate air pollution in contributing to adverse pregnancy outcomes and how these mechanisms intersect with those related to socioeconomic status. Here we review the role of oxidative stress, inflammation and endocrine modification in the pathoetiology of deficient deep placentation and detail how the physical and social environments can act alone and collectively to mediate the established pathology linked to a spectrum of adverse pregnancy outcomes. We review the experimental and epidemiological literature showing that diet/nutrition, smoking, and psychosocial stress share similar pathways with that of particulate air pollution exposure to potentially exasperate the negative effects of either insult alone. Therefore, socially patterned risk factors often treated as nuisance parameters should be explored as potential effect modifiers that may operate at multiple levels of social geography. The degree to which deleterious exposures can be ameliorated or exacerbated via community-level social and environmental characteristics needs further exploration.