Longitudinal serum concentrations of placental growth factor: evidence for abnormal placental angiogenesis in pathologic pregnancies

Metformin inhibits activation of NLRP3 inflammasome and inflammatory response in preeclamptic rats

BACKGROUD

It is widely acknowledged that Metformin (MET), an established medication for managing type 2 diabetes, possesses diverse pharmacological effects. This study aims to investigate the protective effects of MET against Nω-Nitro-L-arginine methyl ester (L-NAME)-induced preeclampsia (PE).

METHODS

Sprague Dawley (SD) rats were exposed to 200 mg/kg L-NAME with or without prior MET treatment. Histopathological analysis was performed using Hematoxylin and Eosin staining. Serum levels of inflammatory, antiangiogenic, and angiogenic factors were quantified using ELISA kits. Immunohistochemistry (IHC) staining was employed to observe NLRP3 and IL-1β expressions in placental tissues. Western blot and Quantitative Real-Time PCR (q-PCR) analyses were conducted to assess protein and mRNA expressions of NLRP3, caspase-1, ASC, and IL-1β.

RESULTS

We found that MET could mitigate placental histopathological deterioration and improve pregnancy outcomes in L-NAME-induced PE rat models. MET not only suppressed L-NAME-induced elevation of antiangiogenic factors but also stimulated the production of pro-angiogenic factors. Additionally, MET treatment reversed the excessive inflammatory response induced by L-NAME. Furthermore, MET inhibited the activation of the NLRP3 inflammasome triggered by L-NAME, evidenced by the downregulation of NLRP3 expression, caspase-1, and IL-1β.

CONCLUSIONS

MET demonstrates a protective effect against L-NAME-induced PE rats, potentially mediated through inhibition of the inflammatory response, downregulation of NLRP3 inflammasome expression in the placenta, and regulation of the balance between anti-angiogenic and pro-angiogenic factors.

Maternal Blood Angiogenic Factors and the Prediction of Critical Adverse Perinatal Outcomes Among Small-for-Gestational-Age Pregnancies

OBJECTIVE

Our objective was to determine whether maternal blood angiogenic factors in suspected-small-for-gestational-age (sSGA) fetuses can predict critical adverse perinatal outcomes (CAPO) and improve risk assessment.

METHODS

Women with singleton pregnancies diagnosed with sSGA, between 24 and 356/7 weeks' gestation, were included. Clinical and sonographic comprehensive evaluations were performed at enrolment. Plasma angiogenic factors, soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF), were obtained at diagnosis. In parallel, three attending maternal-fetal-medicine specialists predicted the risk (1-5 scale) of these pregnancies to develop CAPO, based on the clinical presentation. CAPOs were defined as prolonged neonatal intensive care unit hospitalization, fetal or neonatal death, and major neonatal morbidity. Statistical analysis included sensitivity, specificity, positive and negative predictive values, and receiver-operating characteristic (ROC) curve analyses.

RESULTS

Of the 79 cases included, 32 were complicated by CAPO (40.5%). In SGA fetuses with CAPO, the sFlt-1/PlGF ratio was higher (p < 0.001) and PlGF was lower (p < 0.001) as compared with uncomplicated pregnancies. The areas under the ROC curves for specialists were 0.913, 0.824, and 0.811 and for PlGF and sFlt-1/PlGF ratio 0.926 and 0.900, respectively. CAPO was more common in pregnancies with absent end-diastolic flow or reversed end-diastolic flow (AEDF or REDF) in the umbilical artery upon enrolment (91.6%). Yet, 65.6% of cases involving CAPO occurred in patients without AEDF or REDF, and 66.6% of these cases were not identified by one or more of the experts. The sFlt-1/PlGF ratio identified 92.9% of the experts' errors in this group and 100% of the errors in cases with AEDF or REDF.

CONCLUSION

Among sSGA pregnancies prior to 36 weeks' gestation, angiogenic factors testing can identify most cases later complicated with CAPO. Our data demonstrate for the first time that these markers can reduce clinician judgment errors. Incorporation of these measures into decision-making algorithms could potentially improve management, outcomes, and even health care costs.

KEY POINTS

· Angiogenic factors at diagnosis of sSGA can be used to predict CAPO.. · The sFlt-1/PlGF ratio can flag sSGA pregnancies at increased risk.. · The sFlt-1/PlGF ratio at admission of sSGA adds to clinical assessment..

Does Developing Interpregnancy Hypertension Affect the Recurrence Risk of Preeclampsia? A Population-Based Cohort Study

BACKGROUND

Preeclampsia in a first pregnancy is a strong risk factor for preeclampsia in a second pregnancy. Whether chronic hypertension developed after a first pregnancy (interpregnancy hypertension) affects the recurrence risk of preeclampsia is unknown.

METHODS

This is a population-based cohort study of 391,645 women with their first and second singleton births between 2006 and 2017. Exposure groups were women with preeclampsia in their first pregnancy, interpregnancy hypertension, or both risk factors. Women with neither risk factor were used as a reference group. We calculated the adjusted relative risk (aRR) with 95% confidence intervals (CIs) for overall preeclampsia in the second pregnancy as well as preterm (<37 gestational weeks) and term (≥37 gestational weeks) subgroups of the disease.

RESULTS

Women with preeclampsia in their first pregnancy who did or did not develop interpregnancy hypertension had rates of preeclampsia in their second pregnancy of 21.5% and 13.6%, respectively. In the same population, the corresponding rates of preterm preeclampsia were 5.5% and 2.6%, respectively. After adjusting for maternal factors, women with preeclampsia in their first pregnancy who developed interpregnancy hypertension and those who did not have almost the same risk of overall preeclampsia in their second pregnancy (aRRs with 95% CIs: 14.51; 11.77-17.89 and 12.83; 12.09-13.62, respectively). However, preeclampsia in the first pregnancy and interpregnancy hypertension had a synergistic interaction on the outcome of preterm preeclampsia (aRR with 95% CI 26.66; 17.44-40.80).

CONCLUSIONS

Women with previous preeclampsia who developed interpregnancy hypertension had a very high rate of preterm preeclampsia in a second pregnancy, and the two risk factors had a synergistic interaction.

Disruption of maternal vascular remodeling by a fetal endoretrovirus-derived gene in preeclampsia

BACKGROUND

Preeclampsia, one of the most lethal pregnancy-related diseases, is associated with the disruption of uterine spiral artery remodeling during placentation. However, the early molecular events leading to preeclampsia remain unknown.

RESULTS

By analyzing placentas from preeclampsia, non-preeclampsia, and twin pregnancies with selective intrauterine growth restriction, we show that the pathogenesis of preeclampsia is attributed to immature trophoblast and maldeveloped endothelial cells. Delayed epigenetic reprogramming during early extraembryonic tissue development leads to generation of excessive immature trophoblast cells. We find reduction of de novo DNA methylation in these trophoblast cells results in selective overexpression of maternally imprinted genes, including the endoretrovirus-derived gene PEG10 (paternally expressed gene 10). PEG10 forms virus-like particles, which are transferred from the trophoblast to the closely proximate endothelial cells. In normal pregnancy, only a low amount of PEG10 is transferred to maternal cells; however, in preeclampsia, excessive PEG10 disrupts maternal vascular development by inhibiting TGF-beta signaling.

CONCLUSIONS

Our study reveals the intricate epigenetic mechanisms that regulate trans-generational genetic conflict and ultimately ensure proper maternal-fetal interface formation.

Novel Associations Between Mid-Pregnancy Cardiovascular Biomarkers and Preeclampsia: An Explorative Nested Case-Control Study

Prediction of women at high risk of preeclampsia is important for prevention and increased surveillance of the disease. Current prediction models need improvement, particularly with regard to late-onset preeclampsia. Preeclampsia shares pathophysiological entities with cardiovascular disease; thus, cardiovascular biomarkers may contribute to improving prediction models. In this nested case-control study, we explored the predictive importance of mid-pregnancy cardiovascular biomarkers for subsequent preeclampsia. We included healthy women with singleton pregnancies who had donated blood in mid-pregnancy (~ 18 weeks' gestation). Cases were women with subsequent preeclampsia (n = 296, 10% of whom had early-onset preeclampsia [< 34 weeks]). Controls were women who had healthy pregnancies (n = 333). We collected data on maternal, pregnancy, and infant characteristics from medical records. We used the Olink cardiovascular II panel immunoassay to measure 92 biomarkers in the mid-pregnancy plasma samples. The Boruta algorithm was used to determine the predictive importance of the investigated biomarkers and first-trimester pregnancy characteristics for the development of preeclampsia. The following biomarkers had confirmed associations with early-onset preeclampsia (in descending order of importance): placental growth factor (PlGF), matrix metalloproteinase (MMP-12), lectin-like oxidized LDL receptor 1, carcinoembryonic antigen-related cell adhesion molecule 8, serine protease 27, pro-interleukin-16, and poly (ADP-ribose) polymerase 1. The biomarkers that were associated with late-onset preeclampsia were BNP, MMP-12, alpha-L-iduronidase (IDUA), PlGF, low-affinity immunoglobulin gamma Fc region receptor II-b, and T cell surface glycoprotein. Our results suggest that MMP-12 is a promising novel preeclampsia biomarker. Moreover, BNP and IDUA may be of value in enhancing prediction of late-onset preeclampsia.

Validation of a new kit for preeclampsia screening: A comprehensive analysis

Objectives

Preeclampsia is a common pregnancy complication that significantly contributes to maternal mortality, perinatal mortality, and preterm delivery. The sFlt-1/PlGF (fms-like tyrosine kinase-1/placental growth factor) ratio has demonstrated robust diagnostic value for preeclampsia. This study assessed the analytical performance and diagnostic accuracy of a novel quantitative determination kit for sFlt-1 and PlGF for the diagnosis of preeclampsia.

Methods

The detection performance of the test kit was validated using the Center for Medical Device Evaluation (CMDE) and Clinical and Laboratory Standards Institute (CLSI) documents. The test results were compared to those of the Elecsys immunoassay (Roche Diagnostics). Independent discovery and validation sets were used to analyze the diagnostic efficacy of the preeclampsia kit. The area under the curve (AUC) for preeclampsia at different gestational ages was calculated.

Results

Correlation analysis between the test and Roche kits revealed a strong concordance (sFlt-1: r = 0.9966, P < 0.0001; PlGF: r = 0.9935, P < 0.0001). The AUCs for sFlt-1, PlGF, and the sFlt-1/PlGF ratio in diagnosing preeclampsia were 0.749, 0.795, and 0.834, respectively, in the discovery set and 0.729, 0.811, and 0.831, respectively, in the validation set. The corresponding results from the Roche kit were 0.741, 0.795, and 0.829, respectively, and 0.761, 0.864, and 0.844, respectively.

Conclusions

Quantitative sFlt-1 and PlGF kits exhibited high levels of consistency with the Roche kits in terms of quantitative outcomes and diagnostic performance for preeclampsia.

Neurodevelopmental Disruptions in Children of Preeclamptic Mothers: Pathophysiological Mechanisms and Consequences

Preeclampsia (PE) is a multisystem disorder characterized by elevated blood pressure in the mother, typically occurring after 20 weeks of gestation and posing risks to both maternal and fetal health. PE causes placental changes that can affect the fetus, particularly neurodevelopment. Its key pathophysiological mechanisms encompass hypoxia, vascular and angiogenic dysregulation, inflammation, neuronal and glial alterations, and disruptions in neuronal signaling. Animal models indicate that PE is correlated with neurodevelopmental alterations and cognitive dysfunctions in offspring and in humans, an association between PE and conditions such as cerebral palsy, autism spectrum disorder, attention deficit hyperactivity disorder, and sexual dimorphism has been observed. Considering the relevance for mothers and children, we conducted a narrative literature review to describe the relationships between the pathophysiological mechanisms behind neurodevelopmental alterations in the offspring of PE mothers, along with their potential consequences. Furthermore, we emphasize aspects pertinent to the prevention/treatment of PE in pregnant mothers and alterations observed in their offspring. The present narrative review offers a current, complete, and exhaustive analysis of (i) the pathophysiological mechanisms that can affect neurodevelopment in the children of PE mothers, (ii) the relationship between PE and neurological alterations in offspring, and (iii) the prevention/treatment of PE.

Predictive value of the sFlt‑1/PlGF ratio in women with suspected preeclampsia: An update (Review)

Preeclampsia (PE) is a major complication of pregnancy with an incidence rate of 2‑8% and is a leading cause of maternal mortality and morbidity. The various consequences of severe preeclampsia for the fetus, neonate and child include intrauterine growth retardation (IUGR), fetal hypoxia, oligohydramnios, intrauterine fetal demise, increased perinatal mortality and morbidity, neurodevelopmental disorders and even irreversible brain damage (cerebral palsy). A number of studies have demonstrated that differences in maternal serum concentrations of angiogenic factors between preeclampsia and normotensive pregnancies can be used as biomarkers, either alone or in combination with other markers, to predict the development of PE. The presence in the maternal circulation of two proteins of placental origin, placental growth factor (PlGF) and soluble fms‑like tyrosine kinase 1 (sFlt‑1), has been shown to be of clinical value, as the sFlt‑1/PlGF ratio appears to be the optimal predictive tool for the development of PE. The measurement of their concentration in maternal serum in screening models, serves as predictive marker for the development of PE or IUGR later in gestation. However, further research is required to improve its clinical applicability and provide guidelines for its use worldwide to achieve more consistent clinical management of women with PE.

Longitudinal Associations between Ambient Air Pollution and Angiogenic Biomarkers among Pregnant Women in the LIFECODES Study, 2006-2008

BACKGROUND

Exposures to ambient air pollution during pregnancy have been linked to adverse pregnancy outcomes such as preeclampsia and fetal growth restriction. Although evidence has shown that women with preeclampsia have higher ratio of soluble fms-like tyrosine kinase 1 to placental growth factor (sFlt-1/PlGF ratio), the potential impact of air pollution on markers of placental growth and function has not been well studied.

OBJECTIVES

We aimed to examine longitudinal associations between ambient air pollution exposure and angiogenic factors among pregnant women in LIFECODES, a prospective birth cohort and biorepository in Massachusetts in the United States.

METHODS

PlGF and sFlt-1 were measured among pregnant women using plasma samples collected around 10, 18, 26, and 35 wk' gestation. Women's exposures to ozone (O 3 ), fine particulate matter with aerodynamic diameter ≤ 2.5 μ m (PM 2.5 ), and nitrogen dioxide (NO 2 ) within 1, 2, 4, and 8 wk prior to each plasma sample collection were estimated based on geocoded residential addresses, and mixed effect linear regression models were fitted to assess their associations with sFlt-1/PlGF ratio, sFlt-1 (ng/mL), and PlGF (pg/mL). Percent changes in outcomes associated with each interquartile range increase in exposures were reported, along with their 95% confidence intervals.

RESULTS

A total of 1,066 pregnant women were included. In the multipollutant models, significant associations were observed for increased sFlt-1/PlGF ratio (PM 2.5 3-8 wk' gestation, NO 2 : 35-39 wk' gestation), elevated sFlt-1 (O 3 : 26-34 wk' gestation, PM 2.5 : 3-8 wk' gestation), decreased sFlt-1 (NO 2 : 4-8 wk' gestation), and decreased PlGF (NO 2 : 34-39 wk' gestation) after adjusting for sociodemographic status, smoking, drinking, body mass index, parity, history of chronic hypertension, and conception time.

DISCUSSION

Exposures to PM 2.5 during early pregnancy and exposures to O 3 and NO 2 during late pregnancy were associated with increased sFlt-1/PlGF ratio, elevated sFlt-1 and with decreased PlGF, which may be a potential mechanism underlying ambient air pollution's impacts on adverse pregnancy and birth outcomes. https://doi.org/10.1289/EHP11909.

Missing links in preeclampsia cell model systems of endothelial dysfunction

Preeclampsia, one of the main hypertensive disorders of pregnancy, is associated with circulating factors released by the ischemic placenta accompanied by systemic endothelial dysfunction. The etiology of preeclampsia remains poorly understood although it is associated with high maternal and fetal mortality and increased cardiovascular disease risk. Most cell model systems used for studying endothelial dysfunction have not taken into account hemodynamic physical factors such as shear-stress forces which may prevent extrapolation of cell data to in vivo settings. We overview the role of hemodynamic forces in modulating endothelial cell function and discuss strategies to reproduce this biological characteristic in vitro to improve our understanding of endothelial dysfunction associated with preeclampsia.

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.

Clinical utility of sFlt-1 and PlGF in screening, prediction, diagnosis and monitoring of pre-eclampsia and fetal growth restriction

Pre-eclampsia (PE) is characterized by placental and maternal endothelial dysfunction, and associated with fetal growth restriction (FGR), placental abruption, preterm delivery and stillbirth. The angiogenic factors soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) are altered in pregnancies complicated by placenta-related disorders. In this Review, we summarize the existing knowledge, examining the performance of maternal PlGF, sFlt-1 and the sFlt-1/PlGF ratio for screening PE, predicting development of PE in the short term, diagnosing PE, monitoring established PE and predicting other placenta-related disorders in singleton pregnancy. We also discuss the performance of PlGF and the sFlt-1/PlGF ratio for predicting PE in twin pregnancy. For first-trimester screening in singleton pregnancy, a more accurate way of identifying high-risk women than current practice is to combine maternal PlGF levels with clinical risk factors and ultrasound markers. Later in pregnancy, the sFlt-1/PlGF ratio has advantages over PlGF because it has a higher pooled sensitivity and specificity for diagnosing and monitoring PE. It has clinical value because it can rule out the development of PE in the 1-4-week period after the test. Once a diagnosis of PE is established, repeat measurement of sFlt-1 and PlGF can help monitor progression of the condition and may inform clinical decision-making regarding the optimal time for delivery. The sFlt-1/PlGF ratio is useful for predicting FGR and preterm delivery, but the association between stillbirth and the angiogenic factors is unclear. The sFlt-1/PlGF ratio can be used to predict PE in twin pregnancy, although different sFlt-1/PlGF ratio cut-offs from those for singleton pregnancy should be applied for optimal performance. In summary, PlGF, sFlt-1 and the sFlt-1/PlGF ratio are useful for screening, diagnosing, predicting and monitoring placenta-related disorders in singleton and twin pregnancy. We propose that tests for these angiogenic factors are integrated more fully into clinical practice.© 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Similar Pro- and Antiangiogenic Profiles Close to Delivery in Different Clinical Presentations of Two Pregnancy Syndromes: Preeclampsia and Fetal Growth Restriction

The purpose of this study was to evaluate serum levels of anti- and pro-angiogenic substances measured using enzyme-linked immunosorbent assays and their ratios in pregnancies complicated by different clinical subsets of placental ischemic syndrome: preeclampsia and/or fetal growth restriction. A prospective case-control study was performed consisting of 77 singleton pregnancies complicated by preeclampsia, preeclampsia with concurrent fetal growth restriction (FGR), and isolated normotensive FGR pairwise matched by gestational age with healthy pregnancies. The entire study cohort was analyzed with respect to adverse pregnancy outcomes that occurred. In all investigated subgroups, placental growth factor (PlGF) was lower and soluble endoglin (sEng), the soluble fms-like tyrosine kinase-1-sFlt-1/PlGF and sFlt-1*sEng/PlGF ratios were higher than in the control group. The differences were most strongly pronounced in the PE with concurrent FGR group and in the sFlt-1/PlGF ratio. The highest sFlt-1 values in preeclamptic patients suggest that this substance may be responsible for reaching the threshold needed for PE to develop as a maternal manifestation of ischemic placental disease. The FGR is characterized by an elevated maternal sFlt-1/PlGF ratio, which boosts at the moment of indicated delivery due to fetal risk. We concluded that angiogenic imbalance is reflective of placental disease regardless of its clinical manifestation in the mother, and may be used as support for the diagnosis and prognosis of FGR.

The Role of Dietary Polyphenols in Pregnancy and Pregnancy-Related Disorders

Polyphenols are a group of phytochemicals with extensive biological functions and health-promoting potential. These compounds are present in most foods of plant origin and their increased widespread availability through the intake of nutritional supplements, fortified foods, and beverages, has also led to increased exposure throughout gestation. In this narrative review, we focus on the role of polyphenols in both healthy and pathological pregnancy. General information related to their classification and function is followed by an overview of their known effects in early-pregnancy events, including the current insights into molecular mechanisms involved. Further, we provide an overview of their involvement in some of the most common pregnancy-associated pathological conditions, such as preeclampsia and gestational diabetes mellitus. Additionally, we also discuss the estimated possible risk of polyphenol consumption on pregnancy outcomes. The consumption of dietary polyphenols during pregnancy needs particular attention considering the possible effects of polyphenols on the mechanisms involved in maternal adaptation and fetal development. Further studies are strongly needed to unravel the in vivo effects of polyphenol metabolites during pregnancy, as well as their role on advanced maternal age, prenatal nutrition, and metabolic risk of the offspring.

Placental Growth Factor in First Trimester of Pregnancy for Prediction of Maternal and Perinatal Adverse Outcomes

Purpose of the study

Placental growth factor (PLGF) is an angiogenic factor in pregnancy. To find out correlation of plasma levels of placental growth factor in first trimester of pregnancy in Indian women who develop maternal and perinatal adverse outcomes was the aim of the study.

Methods

A prospective longitudinal noninterventional study was done in the department of Obstetrics and Gynecology after obtaining ethics approval. After enrolling patients in the first trimester (11 weeks to 13 weeks 6 days), a questionnaire was filled for demographic characteristics. Uterine artery doppler was done for every patient and blood sample (5 ml) was taken by venu puncture of median cubital vein. Serum levels of PLGF were measured by enzyme linked immunosorbent assay using Thermo Scientific Pierce Human PLGF kit (Thermo Fisher Scientific, Inc., Waltham, MA, USA). Patients were followed for their whole antenatal period and delivery outcomes.

Results

Incidence of preeclampsia in our study was 9.3% (15/161) and fetal growth restriction (FGR) was 19.8% (32/161). Neither BMI nor nulliparity was found to have statistically significant correlation with development of preeclampsia. However, history of preeclampsia was found to be significant risk factor for prediction of preeclampsia (p value < 0.04). Plasma levels of PLGF were significantly lower in preeclampsia and FGR group and this difference was statistically significant (p value < 0.04). 7.5% still born occurred in complicated group and 10% needed NNU/NICU admission in this group.

Conclusion

Measuring PLGF levels in first trimester of pregnancy can help in prediction of preeclampsia and FGR.

Placental dysfunction: The core mechanism for poor neurodevelopmental outcomes in the offspring of preeclampsia pregnancies

Preeclampsia (PE) is a leading condition threatening pregnant women and their offspring. The offspring of PE pregnancies have a high risk of poor neurodevelopmental outcomes and neuropsychological diseases later in life. However, the pathophysiology and pathogenesis of poor neurodevelopment remain undetermined. Abnormal placental functions are at the core of most PE cases, and recent research evidence supports that the placenta plays an important role in fetal brain development. Here, we summarize the relationship between abnormal fetal brain development and placental dysfunction in PE conditions, which include the dysfunction of nutrient and gas-waste exchange, impaired angiogenesis stimulation, abnormal neurotransmitter regulation, disrupted special protectors, and immune disorders. All these factors could lead to poor neurodevelopmental outcomes.

Association of fetal sex with angiogenic factors in normotensive and hypertensive pregnancy states

OBJECTIVES

With the incorporation of angiogenic biomarkers into clinical practice, identification of potential modifiers of the angiogenic profile, including fetal sex, is essential.

STUDY DESIGN

In this retrospective cohort analysis, patients with hypertensive disorders of pregnancy (HDP) and normotensive pregnancies were enrolled upon admission to Labor and Delivery. Blood samples for angiogenic factors were assessed using an automated platform. Clinical and demographic information was abstracted from each patient's medical records.

MAIN OUTCOME MEASURES

Soluble fms-like tyrosine kinase-1 (sFlt1) and placental growth factor (PlGF) levels and their ratio in relation to fetal sex in patients with normotensive pregnancies compared to those with HDP were evaluated.

RESULTS

A total of 617 patients were analyzed (299 normotensive, 113 gestational hypertensive, 71 chronic hypertensive, and 134 preeclamptic patients). There was no difference between the number of patients who had a male fetus among preeclampsia and normotensive parturients (56.0 % vs 50.2 %, p = 0.26). Normotensive patients carrying a male fetus had significantly higher sFlt1 (pg/ml) (3168 [IQR: 2160-4945] vs 2678 [IQR: 1752-4271]; p = 0.01) and sFlt1/PlGF ratios (18 [IQR: 7-44] vs 12 [IQR: 5-30]; p = 0.01) in comparison to pregnant patients carrying a female fetus. This difference between fetal sexes was not observed in the angiogenic profile of patients with HDP.

CONCLUSIONS

Our study of primarily Black, obese patients demonstrates that normotensive patients carrying a male fetus have a significantly higher sFlt1 and sFlt1/PlGF ratio as compared to those carrying a female fetus at term gestation. Fetal sex should be considered as a covariate when studying angiogenic factors in normotensive pregnant patients.

Long-term observational study of renal outcome after preeclampsia: Role of soluble fms-like tyrosine kinase-1(sFlt-1)/ placental growth factor (PlGF) and endoglin

Introduction

Preeclampsia (PE) is an important complication of pregnancy that can lead to chronic kidney disease. Soluble fms-like tyrosine kinase-1 (sFlt-1), placental growth factor (PlGF), the sFlt-1/PlGF ratio and endoglin are biomarkers for the differential diagnosis of PE and other diseases. We aimed to explore the correlation of these biomarkers with long-term renal function, blood pressure and the urine albumin/creatinine ratio (UACR) in PE patients.

Methods

34 patients with PE were enrolled. Blood samples for sFlt-1, PlGF, endoglin and the urine albumin/creatinine ratio (UACR) were collected at the time of PE diagnosis (at 35–40 weeks’ gestational age (GA) (87.50% of cases). After delivery, the patients were followed up at three months and one year to assess blood pressure, renal function and the UACR.

Results

Thirty-four PE patients were included, and 17 completed the study. The estimated glomerular filtration rate (eGFR) decreased significantly at three months and one year after follow-up (128.20 ± 10.34 to 120.75 ± 10.166 ml/min/1.73 m² (p = 0.001) at three months and 126.71 ± 9.948 to 114.29 ± 11.274 ml/min/1.73 m² (p < 0.001) at one year). The endoglin level correlated significantly with the eGFR level during PE, but there was no correlation of any biomarker with eGFR, blood pressure, or the UACR at one year.

Conclusion

Women with PE have a reduction of eGFR at three months and one year after the diagnosis of PE. Only endoglin is correlated with eGFR antepartum; however, it is not correlated with long-term renal function, blood pressure or the UACR.

•

Preeclampsia has been suggested to increase the risk of kidney problems.

•

The soluble endoglin level and sFlt-1:PlGF ratio can predict early and late-onset preeclampsia.

•

Analysis of angiogenic factors may be associated with long term renal function.

MicroRNA-30a contributes to pre-eclampsia through regulating the proliferation, apoptosis, and angiogenesis modulation potential of mesenchymal stem cells by targeting AVEN

Pre-eclampsia (PE) is a pregnancy-associated disease related to an unprecedented hypertension attack. Mesenchymal stem cells (MSCs) play a crucial role in PE pathology. . Our research was designed to illustrate the functions of microRNA-30a (miR-30a) in proliferation, apoptosis, and the potential of regulating angiogenesis in MSCs, and to analyze its potential molecular mechanisms. TargetScan software and the luciferase reporter assay were used to forecast and verify the relationship between miR-30a and AVEN. MiR-30a and AVEN expression in the decidual tissue and decidua (d)MSCs of healthy pregnant women and PE patients were assessed using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Cell proliferation, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2 H-tetrazolium bromide (MTT), flow cytometry, and transwell assays were used to evaluate cell proliferation, growth, the cell cycle, apoptosis, and migration. Furthermore, the tube formation ability was evaluated using the human umbilical vein endothelial cell (HUVEC) tube formation assay. AVEN is the target gene of miR-30a. MiR-30a was upregulated in decidual tissues and dMSCs of PE patients. However, AVEN was weakly expressed, and AVEN expression was negatively related to miR-30a levels in decidual tissues and dMSCs of PE patients. Compared to the mimic control group, upregulation of miR-30a inhibited dMSC proliferation and cell growth, promoted G0/G1 phase arrest, and induced apoptosis. Furthermore, the miR-30a mimic transfected dMSC culture supernatant suppressed HTR-8/SVneo cell migration ability and HUVEC tube formation ability. However, AVEN reversed these changes. In conclusion, miR-30a/AVEN may serve as a new axis for PE treatment.

The feasibility of soluble Fms-Like Tyrosine kinase-1 (sFLT-1) and Placental Growth Factor (PlGF) ratio biomarker in predicting preeclampsia and adverse pregnancy outcomes among medium to high risk mothers in Kuala Lumpur, Malaysia

Background

Preeclampsia significantly contributes to maternal and perinatal morbidity and mortality. It is imperative to identify women at risk of developing preeclampsia in the effort to prevent adverse pregnancy outcomes through early intervention. Soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) level changes are noticeable several weeks before the onset of preeclampsia and its related complications. This study evaluated the feasibility of the sFlt-1/PlGF biomarker ratio in predicting preeclampsia and adverse pregnancy outcomes using a single cut-off point of >38.

Methods

This is a prospective cohort study conducted at a single tertiary centre, in an urban setting in Kuala Lumpur, Malaysia, between December 2019 and April 2021. A total of 140 medium to high risk mothers with singleton pregnancies were recruited at ≥20 weeks’ gestation. sFlt-1/PlGF ratio was measured and the participant monitored according to a research algorithm until delivery. The primary outcome measure was incidence of preeclampsia and the secondary outcome measure was incidence of other adverse pregnancy outcomes.

Results

The overall incidence of preeclampsia was 20.7% (29/140). The mean sFlt-1/PlGF ratio was significantly higher in preeclampsia (73.58 ± 93.49) compared to no preeclampsia (13.41 ± 21.63) (p = 0.002). The risk of preeclampsia (adjusted OR 28.996; 95% CI 7.920–106.164; p<0.001) and low Apgar score (adjusted OR 17.387; 95% CI 3.069–98.517; p = 0.028) were significantly higher among women with sFlt-1/PlGF ratio >38 compared with sFLT-1/PlGF ratio ≤38. The area under the receiver-operator characteristic curve (AUC) for a combined approach (maternal clinical characteristics and biomarker) was 86.9% (p<0.001, 95% CI 78.7–95.0) compared with AUC biomarker alone, which was 74.8% (p<0.001, 95% CI 63.3–86.3) in predicting preeclampsia. The test sensitivity(SEN) was 58.6%, specificity (SPEC) 91%,positive predictive value (PPV) 63% and negative predictive value (NPV) 89.3% for prediction of preeclampsia. For predicting a low Apgar score at 5 minutes, the SEN was 84.6%, SPEC 87.4%, PPV 40.7%, and NPV 98.2%; low birth weight with SEN 52.6%,SPEC 86.0%, PPV 37.0%, NPV 92.0%; premature delivery with SEN 48.5%, SPEC 89.5%, PPV 59.3%, NPV 84.7% and NICU admission with SEN 50.0%, SPEC 85.8%, PPV 37.0% and NPV 91.2%.

Conclusions

It is feasible to use single cut-off point of >38 ratio of the biomarkers sFlt-1/PlGF in combination with other parameters (maternal clinical characteristics) in predicting preeclampsia and adverse pregnancy outcomes among medium to high risk mothers without restricting outcome measurement period to 1 and 4 weeks in a single urban tertiary centre in Kuala Lumpur, Malaysia.

How Soluble Fms-Like Tyrosine Kinase 1 Could Contribute to Blood-Brain Barrier Dysfunction in Preeclampsia?

Preeclampsia is a pregnancy-related syndrome that courses with severe cerebrovascular complications if not properly managed. Findings from pre-clinical and clinical studies have proposed that the imbalance between pro- and anti-angiogenic factors exhibited in preeclampsia is a major component of its pathophysiology. In this regard, measurement of circulating levels of soluble tyrosine kinase-1 similar to fms (sFlt-1), a decoy receptor for vascular endothelial growth factor (VEGF), is a moderately reliable biomarker for the diagnosis of preeclampsia. However, few studies have established a mechanistic approach to determine how the high levels of sFlt-1 are responsible for the endothelial dysfunction, and even less is known about its effects at the blood-brain barrier (BBB). Since the expression pattern of VEGF receptors type 1 and 2 in brain endothelial cells differs from the observed in peripheral endothelial cells, and components of the neurovascular unit of the BBB provide paracrine secretion of VEGF, this compartmentalization of VEGF signaling could help to see in a different viewpoint the role of sFlt-1 in the development of endothelial dysfunction. In this article, we provide a hypothesis of how sFlt-1 could eventually be a protective factor for brain endothelial cells of the BBB under preeclampsia.

Imbalances in circulating angiogenic factors in the pathophysiology of preeclampsia and related disorders

Preeclampsia is a devastating medical complication of pregnancy that can lead to significant maternal and fetal morbidity and mortality. It is currently believed that there is abnormal placentation in as early as the first trimester in women destined to develop preeclampsia. Although the etiology of the abnormal placentation is being debated, numerous epidemiologic and experimental studies suggest that imbalances in circulating angiogenic factors released from the placenta are responsible for the maternal signs and symptoms of preeclampsia. In particular, circulating levels of soluble fms-like tyrosine kinase 1, an antiangiogenic factor, are markedly increased in women with preeclampsia, whereas free levels of its ligand, placental, growth factor are markedly diminished. Alterations in these angiogenic factors precede the onset of clinical signs of preeclampsia and correlate with disease severity. Recently, the availability of automated assays for the measurement of angiogenic biomarkers in the plasma, serum, and urine has helped investigators worldwide to demonstrate a key role for these factors in the clinical diagnosis and prediction of preeclampsia. Numerous studies have reported that circulating angiogenic biomarkers have a very high negative predictive value to rule out clinical disease among women with suspected preeclampsia. These blood-based biomarkers have provided a valuable tool to clinicians to accelerate the time to clinical diagnosis and minimize maternal adverse outcomes in women with preeclampsia. Angiogenic biomarkers have also been useful to elucidate the pathogenesis of related disorders of abnormal placentation such as intrauterine growth restriction, intrauterine fetal death, twin-to-twin transfusion syndrome, and fetal hydrops. In summary, the discovery and characterization of angiogenic proteins of placental origin have provided clinicians a noninvasive blood-based tool to monitor placental function and health and for early detection of disorders of placentation. Uncovering the mechanisms of altered angiogenic factors in preeclampsia and related disorders of placentation may provide insights into novel preventive and therapeutic options.

Relationship between the sFlt-1/PlGF ratio and the optical coherence tomographic features of chorioretina in patients with preeclampsia

This study aimed to evaluate the correlation between ophthalmologic factors and the serologic indicator soluble fms-like tyrosine kinase 1 (sFlt-1): placental growth factor (PlGF) ratio in patients with preeclampsia using optical coherence tomography (OCT) and OCT angiography (OCT-A). A total of 52 pregnant patients (104 eyes) diagnosed with preeclampsia were recruited during their hospital stay. The associations between the sFlt-1/PlGF ratio and chorioretinal measurements, including the choroidal thickness (CT), foveal avascular zone, vascular density, and ganglion cell layer+ were evaluated. Central and nasal subfield CT of the left eye (p = 0.039; p = 0.010) and nasal subfield CT of the right eye (p = 0.042) were lower in the high sFlt-1/PlGF ratio group (≥38). Pearson’s correlation test showed a negative correlation between the sFlt-1/PlGF ratio and central subfield CT; however, this was not statistically significant (p = 0.648). Linear regression analysis revealed a significant association between the sFlt-1/PlGF ratio and central subfield CT (β coefficient, -6.66; p = 0.01) and between sFlt-1 and central subfield CT (β coefficient, -5.65; p = 0.00). Thus, an increase in the sFlt-1/PlGF ratio resulted in a decrease in central subfield CT.

Circulating EGFL7 distinguishes between IUGR and PE: an observational case-control study

Isolated intrauterine growth restriction (IUGR) and preeclampsia (PE) share common placental pathogenesis. Differently from IUGR, PE is a systemic disorder which may also affect liver and brain. Early diagnosis of these conditions may optimize maternal and fetal management. Aim of this study was to assess whether Epidermal Growth Factor-Like domain 7 (EGFL7) dosage in maternal blood discriminates between isolated IUGR and PE. A total of 116 women were enrolled in this case–control study: 12 non-pregnant women, 34 healthy pregnant women, 34 women presenting with isolated IUGR and 36 presenting with PE. Levels of circulating EGFL7 and other known pro- and anti-angiogenic factors were measured by ELISA at different gestational ages (GA). Between 22–25 weeks of gestation, EGFL7 levels in early-onset PE (e-PE) plasma samples were significantly higher than those measured in controls or isolated IUGR samples (69.86 ± 6.17 vs. 19.8 ± 2.5 or 18.8 ± 2.8 µg/ml, respectively). Between 26–34 weeks, EGFL7 levels remained significantly higher in e-PE compared to IUGR. At term, circulating and placental EGFL7 levels were comparable between IUGR and late-onset PE (l-PE). In contrast, circulating levels of PlGF were decreased in both IUGR- and PE- complicated pregnancies, while levels of both sFLT-1 and sENDOGLIN were increased in both conditions. In conclusion, EGFL7 significantly discriminates between isolated IUGR and PE.

HIV Associated Preeclampsia: A Multifactorial Appraisal

Introduction: This review explores angiogenesis, vascular dysfunction, the complement system, RAAS, apoptosis and NETosis as potential pathways that are dysregulated during preeclampsia, HIV infection and ART usage. Results: HIV-1 accessory and matrix proteins are protagonists for the elevation of oxidative stress, apoptosis, angiogenesis, and elevation of adhesion markers. Despite the immunodeficiency during HIV-1 infection, HIV-1 exploits our cellular defence arsenal by escaping cell-mediated lysis, yet HIV-1 infectivity is enhanced via C5a release of TNF-α and IL-6. This review demonstrates that PE is an oxidatively stressed microenvironment associated with increased apoptosis and NETosis, but with a decline in angiogenesis. Immune reconstitution in the duality of HIV-1 and PE by protease inhibitors, HAART and nucleoside reverse transcriptase, affect similar cellular pathways that eventuate in loss of endothelial cell integrity and, hence, its dysfunction. Conclusions: HIV-1 infection, preeclampsia and ARTs differentially affect endothelial cell function. In the synergy of both conditions, endothelial dysfunction predominates. This knowledge will help us to understand the effect of HIV infection and ART on immune reconstitution in preeclampsia.

Placental growth factor is negatively regulated by epidermal growth factor receptor (EGFR) signaling

INTRODUCTION

Preeclampsia is associated with reduced pro-angiogenic Placental Growth Factor (PlGF) and increased levels of anti-angiogenic soluble FMS like tyrosine kinase-1 (sFlt-1). We have previously shown that sFlt-1 secretion is positively regulated via the Epidermal Growth Factor Receptor (EGFR) and mitochondrial respiration pathways. We assessed whether these pathways also regulate endothelial and placental secretion of PlGF.

METHODS

Primary cytotrophoblast cells and primary human umbilical vein endothelial cells (HUVECs) were treated with EGFR inhibitor gefitinib, or small molecules that inhibit down-stream pathways of the receptor: U0126, PD98059 (ERK/MEK pathway inhibitors), ZM336372 (JAK/STAT inhibitor) or AG490 (JAK inhibitor). We inhibited mitochondrial respiration in primary cytotrophoblasts using mitochondrial complex inhibitors rotenone (complex I), antimycin (complex III) or oligomycin (complex IV). We then measured PlGF secretion in the condition media.

RESULTS

Three inhibitors of the EGFR pathway significantly increased PlGF secretion: gefitinib (p = 0.03), AG490 (p < 0.0001) and U0126 (p = 0.03) in primary cytotrophoblasts, while PD98059 reduced PlGF secretion (p = 0.002). In the same cells, neither gefitinib or UO126 altered PlGF mRNA expression, but AG490 significantly increased its expression (p = 0.02). Primary endothelial cell PlGF secretion was significantly reduced when treated with PD98059 and U0126 while ZM336372 had no effect. Rotenone significantly reduced cytotrophoblast PlGF secretion (p = 0.0005). Neither antimycin (p = 0.9) or oligomycin (p = 0.9) had an effect.

DISCUSSION

We have shown that PlGF secretion from primary cytotrophoblast and HUVECs is altered by inhibiting EGFR signaling and potentially mitochondrial respiration, coincident with reduced sFlt-1 secretion. This suggests that common pathways are regulating both pro and anti-angiogenic molecules that are changed in association with preeclampsia and provides insight into the pathogenesis of this serious disease.

Healthy and preeclamptic pregnancies show differences in Guanylate-Binding Protein-1 plasma levels

The large interferon-inducible anti-angiogenic pro-inflammatory GTPase Guanylate Binding Protein-1 (GBP-1) is produced and secreted by activated endothelial cells and is highly induced by inflammatory cytokines and inhibited by angiogenic growth factors. During pregnancy a generalized mild inflammatory response is observed. During preeclampsia this generalized inflammatory response is even further activated and activation of the endothelium occurs. We hypothesized that GBP-1 is increased in healthy pregnancy and will be even further increased during preeclampsia. In the first experiment, plasma and placentas were collected from healthy and preeclamptic pregnancies. Plasma was also collected from non-pregnant women. For the second experiment longitudinal blood samples from women with a healthy or preeclamptic pregnancy were collected from the end of the first trimester until birth and one sample postpartum. The plasma GBP-1 levels were measured by ELISA and GBP-1 mRNA and protein levels in the placenta were tested by qPCR and immunohistochemistry. During pregnancy higher plasma concentrations of GBP-1 compared with non-pregnant women were observed. Surprisingly, during preeclampsia, plasma GBP-1 levels were lower than in control pregnancies and similar to the level of non-pregnant controls. Placental GBP-1 mRNA levels were not different between healthy and preeclamptic pregnancies and GBP-1 protein was virtually undetectable in the trophoblast by immunohistochemistry in placental tissue. Evaluation of longitudinal samples showed that plasma GBP-1 concentrations increased towards the end of pregnancy in healthy pregnancies, but not in preeclampsia. In line with our hypothesis, we found higher GBP-1 plasma levels during healthy pregnancy. However, plasma GBP-1 did not further increase during preeclampsia, but was stable. Further studies are needed to evaluate why GBP-1 does not increase during preeclampsia.

Acid Sensing Ion Channel 2a Is Reduced in the Reduced Uterine Perfusion Pressure Mouse Model and Increases Seizure Susceptibility in Pregnant Mice

Eclampsia is diagnosed in pregnant women who develop novel seizures. Our laboratory showed that the reduced uterine perfusion pressure (RUPP) rat model of preeclampsia displays reduced latency to drug-induced seizures. While acid sensing ion channels (ASIC1a and 3) are important for reducing seizure longevity and severity, the role of ASIC2a in mediating seizure sensitivity in pregnancy has not been investigated. We hypothesized that 1) RUPP reduces hippocampal ASIC2a, and 2) pregnant mice with reduced ASIC2a (ASIC2a+/-) have increased seizure sensitivity. On gestational day 18.5, hippocampi from sham and RUPP C57BL/6 mice were harvested, and ASIC2a was assessed using Western blot. Pregnant wild-type and ASIC2a+/- mice received 40 mg/kg of pentylenetetrazol (i.p.) and were video recorded for 30 min. Behaviors were scored using a modified Racine scale (0-7: 0 = no seizure; 7 = respiratory arrest/death). Seizure severity was classified as mild (score = 1-3) or severe (score = 4-7). RUPP mice had reduced hippocampal and placental ASIC2a protein. ASIC2a+/- mice had reduced latency to seizures, increased seizure duration, increased severe seizure duration, and higher maximum seizure scores. Reduced hippocampal ASIC2a in RUPP mice and increased seizure activity in pregnant ASIC2a+/- mice support the hypothesis that reduced ASIC2a increases seizure sensitivity associated with the RUPP.

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.

Multiomics Characterization of Preterm Birth in Low- and Middle-Income Countries

IMPORTANCE

Worldwide, preterm birth (PTB) is the single largest cause of deaths in the perinatal and neonatal period and is associated with increased morbidity in young children. The cause of PTB is multifactorial, and the development of generalizable biological models may enable early detection and guide therapeutic studies.

OBJECTIVE

To investigate the ability of transcriptomics and proteomics profiling of plasma and metabolomics analysis of urine to identify early biological measurements associated with PTB.

DESIGN, SETTING, AND PARTICIPANTS

This diagnostic/prognostic study analyzed plasma and urine samples collected from May 2014 to June 2017 from pregnant women in 5 biorepository cohorts in low- and middle-income countries (LMICs; ie, Matlab, Bangladesh; Lusaka, Zambia; Sylhet, Bangladesh; Karachi, Pakistan; and Pemba, Tanzania). These cohorts were established to study maternal and fetal outcomes and were supported by the Alliance for Maternal and Newborn Health Improvement and the Global Alliance to Prevent Prematurity and Stillbirth biorepositories. Data were analyzed from December 2018 to July 2019.

EXPOSURES

Blood and urine specimens that were collected early during pregnancy (median sampling time of 13.6 weeks of gestation, according to ultrasonography) were processed, stored, and shipped to the laboratories under uniform protocols. Plasma samples were assayed for targeted measurement of proteins and untargeted cell-free ribonucleic acid profiling; urine samples were assayed for metabolites.

MAIN OUTCOMES AND MEASURES

The PTB phenotype was defined as the delivery of a live infant before completing 37 weeks of gestation.

RESULTS

Of the 81 pregnant women included in this study, 39 had PTBs (48.1%) and 42 had term pregnancies (51.9%) (mean [SD] age of 24.8 [5.3] years). Univariate analysis demonstrated functional biological differences across the 5 cohorts. A cohort-adjusted machine learning algorithm was applied to each biological data set, and then a higher-level machine learning modeling combined the results into a final integrative model. The integrated model was more accurate, with an area under the receiver operating characteristic curve (AUROC) of 0.83 (95% CI, 0.72-0.91) compared with the models derived for each independent biological modality (transcriptomics AUROC, 0.73 [95% CI, 0.61-0.83]; metabolomics AUROC, 0.59 [95% CI, 0.47-0.72]; and proteomics AUROC, 0.75 [95% CI, 0.64-0.85]). Primary features associated with PTB included an inflammatory module as well as a metabolomic module measured in urine associated with the glutamine and glutamate metabolism and valine, leucine, and isoleucine biosynthesis pathways.

CONCLUSIONS AND RELEVANCE

This study found that, in LMICs and high PTB settings, major biological adaptations during term pregnancy follow a generalizable model and the predictive accuracy for PTB was augmented by combining various omics data sets, suggesting that PTB is a condition that manifests within multiple biological systems. These data sets, with machine learning partnerships, may be a key step in developing valuable predictive tests and intervention candidates for preventing PTB.

A prospective study of placental growth factor in twin pregnancy and development of a dichorionic twin pregnancy specific reference range

OBJECTIVE

To develop a dichorionic twin pregnancy specific reference range for placental growth factor (PlGF), and to compare gestation-specific placental growth factor levels in twin pregnancies later complicated by pre-eclampsia, hypertensive disorder of pregnancy or fetal growth restriction with control pregnancies.

DESIGN

Prospective observational study.

SETTING

Single large tertiary maternity unit in Ireland.

POPULATION OR SAMPLE

Women with a twin pregnancy.

METHODS

Consenting pregnant women, across a variety of gestations, had a single blood sample taken at one time-point only during their pregnancy. The plasma was initially biobanked and PlGF was measured later in batches using the point of care Triage^® PlGF test.

MAIN OUTCOME MEASURES

Development of pre-eclampsia, hypertensive disorder of pregnancy or fetal growth restriction.

RESULTS

Placental growth factor levels in uncomplicated dichorionic twin pregnancies were significantly lower in the women who later developed pre-eclampsia than in the controls at all gestational intervals. In those that later developed any hypertensive disorder of pregnancy, median PlGF was lower only in those recruited before 24 weeks of gestation, whereas in infants with a customised birthweight below the third centile, PlGF was lower only in those sampled after 24 weeks of gestation.

CONCLUSIONS

Placental growth factor levels in twin pregnancy differ significantly between those women with a pregnancy that will later be complicated by pre-eclampsia and those that will not. This difference is present many weeks before clinical signs or symptoms of disease are present. Using cross-sectional values from uncomplicated twin pregnancies, we have developed a dichorionic twin pregnancy specific reference range for PlGF.

TWEETABLE ABSTRACT

Placental growth factor levels in twin pregnancy differ significantly between women that will later develop pre-eclampsia and those that will not.

Regulation of Uterine Spiral Artery Remodeling: a Review

Extravillous trophoblast remodeling of the uterine spiral arteries is essential for promoting blood flow to the placenta and fetal development, but little is known about the regulation of this process. A defect in spiral artery remodeling underpins adverse conditions of human pregnancy, notably early-onset preeclampsia and fetal growth restriction, which result in maternal and fetal morbidity and mortality. Many in vitro studies have been conducted to determine the ability of growth and other factors to stimulate trophoblast cells to migrate across a synthetic membrane. Clinical studies have investigated whether the maternal levels of various factors are altered during abnormal human pregnancy. Animal models have been established to assess the ability of various factors to recapitulate the pathophysiological symptoms of preeclampsia. This review analyzes the results of the in vitro, clinical, and animal studies and describes a nonhuman primate experimental paradigm of defective uterine artery remodeling to study the regulation of vessel remodeling.

The impact of maternal asthma during pregnancy on fetal growth and development: a review

INTRODUCTION

Asthma is a highly prevalent co-morbidity during pregnancy that can worsen as gestation progresses and is associated with several adverse perinatal outcomes. These adverse outcomes often result from uncontrolled asthma during pregnancy and acute asthma exacerbations that are associated with alterations in placental function and fetal growth.

AREAS COVERED

This paper will discuss how maternal asthma in pregnancy affects fetal growth and development which may alter future offspring health. Changes in placental function occur in a sex-specific manner in pregnancies complicated by asthma and result in differences in fetal growth and development which may influence child health. The follow up of children from mothers with asthma suggests they are at greater risk of developing asthma, have alterations in microvascular structure that may contribute to a future risk of cardiovascular disease and epigenetic modifications in immune cell function. The current evidence suggests that appropriately managed asthma during pregnancy results in normal fetal growth and development.

EXPERT OPINION

Clinical management of asthma during pregnancy needs significant improvement to prevent adverse outcomes for the fetus. The key to improving maternal and fetal outcomes is through education of health professionals and parents about controlling asthma during pregnancy.

Preserved efficiency of sickle cell disease placentas despite altered morphology and function

INTRODUCTION

Pregnant women with sickle cell disease (SCD) are at high risk for sickle cell-related complications, obstetrical complications, and perinatal morbidity. Chronic inflammation and the proangiogenic environment associated with SCD have been associated with endothelial damage. It is unknown whether SCD complications could be associated with placental dysfunction or abnormal placental morphology. Moreover, circulating angiogenic factors in pregnant women with SCD are unexplored.

METHODS

Clinical records, placental and blood samples were collected at term delivery for 21 pregnant patients with SCD and 19 HbAA pregnant controls with adapted to gestational age birth weight newborns. Histological and stereological analyses and scanning electron microscopy (SEM) of the placenta, and PlGF and sFlt1 measurements in blood were performed.

RESULTS

In the SCD group, the parenchyma-forming villi of placentas were thinner than in controls, and increased fibrinoid necrosis and an overabundance of syncytial knots were seen. SEM revealed elongated intermediate villous endings with a reduction in the number of terminal villi compared to controls, indicating a significant branching defect in SCD placentas. Finally, SCD patients had an imbalance in the angiogenic ratio of sFlt1/PlGF (p = 0.008) with a drop of PlGF concentrations.

DISCUSSION

We evidence for the first time both abnormal placenta morphology and altered sFlt1/PlGF ratio in SCD patients, uncorrelated with maintained placental efficiency and fetal growth.

The role of serum interleukin-37 levels, inflammation and blood pressure in patients with preeclampsia

AIM

Preeclampsia is one of the major causes of perinatal, fetal, and maternal mortality and morbidity. The aim of this study was to investigate the association of serum interleukin 37 (IL 37) with preeclampsia.

METHODS

39 women with preeclampsia were included as the study group. 38 healthy, and normotensive pregnant women, at similar gestational week with similar gravidity volunteered as the control group. Clinical findings, biochemical parameters, maternal and perinatal outcomes, and the serum concentrations of IL37 were compared between the groups. The relationship of IL 37 concentrations with clinical findings and blood pressure outcomes were also investigated.

RESULTS

Maternal serum IL 37 concentrations were significantly higher in patients with preeclampsia compared to the healthy pregnant women in the control group (p = .005). IL 37 positively correlated systolic blood pressure (BP) (r = 0.344, p = .002), and diastolic BP (r = 0.332, p = .003). IL 37 was identified as an independent predictor of preeclampsia.

CONCLUSIONS

Serum IL 37 concentrations were higher in preeclamptic patients compared to healthy pregnant women. Furthermore, IL 37 concentrations achieved success in identifying preeclampsia with hypertension. Increased IL 37 activity may have a role in the pathophysiology of preeclampsia.

The impact of maternal asthma during pregnancy on offspring retinal microvascular structure and its relationship to placental growth factor production in utero

Asthma is a common chronic disease in pregnancy that affects placental function and fetal growth and associated with cardio-metabolic disorders in the offspring but the mechanisms are unknown. This study explored whether maternal asthma in pregnancy is associated with the development of offspring microvascular structure and whether it was related to biomarkers of angiogenesis in utero. Children aged 4 to 6 years, born to either asthmatic mothers (n = 38) or healthy controls (n = 25), had their retinal microvascular structure examined. Maternal plasma PlGF concentrations at 18 and 36 weeks' gestation were measured. There was a significant global difference in all retinal microvascular measures between children of asthmatic mothers relative to controls and increased retinal venular tortuosity in children born to asthmatic mothers (7.1 (95% CI 0.7-13.5); P = .031). A rise in plasma PlGF from 18 to 36 weeks' gestation was observed in the control population which was significantly lower in the asthma group by 190.9 pg/mL. PlGF concentrations were correlated with microvascular structure including arteriolar branching and venular tortuosity. These exploratory findings indicate that exposure to maternal asthma during pregnancy is associated with persistent changes in microvascular structure in childhood that may be driven by alterations to angiogenic mechanisms in utero.

Soluble fms-like tyrosine kinase 1 and placental growth factor ratio for predicting preeclampsia in elderly gravida

Objective: To determine the predictive value of plasma soluble fms-like tyrosine kinase 1 (sFlt-1) and placental growth factor (PlGF) ratio for detection of preeclampsia in elderly gravida at 16-18 weeks of gestation and to identify whether abnormalities of this ratio are associated with any other pregnancy complications or not.Methods: Blood samples of 300 cases were collected. Plasma sFlt-1 and PlGF levels were measured using an automated immunoassay.Results: Sensitivity and specificity for plasma sFlt-1/PlGF ratio above 9.8 for preeclampsia prediction were 85.7% and 61.2%, respectively. The sensitivity and specificity to predict early onset preeclampsia were 100% and 61.1%, respectively. Women with abnormal plasma sFlt-1/PlGF ratio were not associated with any other pregnancy complications.Conclusion:  sFlt-1/PlGF ratio at 16-18 weeks of gestation in elderly gravida has a high sensitivity for predicting preeclampsia, especially early onset preeclampsia.

An Insight into the Angiogenic and Lymphatic Interplay in Pre-eclampsia Comorbid with HIV Infection

PURPOSE OF REVIEW

To provide insight on the imbalance of angiogenic and lymphangiogenic factors in pre-eclampsia, as well as highlight polymorphism in genes related to angiogenesis and lymphangiogenesis.

RECENT FINDINGS

The pregnancy-specific disorder pre-eclampsia is diagnosed by the presence of hypertension with/without proteinuria, after 20 weeks of gestation. The pathogenesis of pre-eclampsia remains ambiguous, but research over the years has identified an imbalance in maternal and foetal factors. Familial predisposition and gene variation are also linked to pre-eclampsia development. The sFlt-1/PIGF ratio has attracted great attention over the years; more recently several researchers have reported that a sFlt-1/PIGF ratio of ≤ 38 can be used to predict short-term absence of pre-eclampsia. This ratio has the potential to prevent adverse pregnancy outcomes and reduce healthcare costs significantly. Genome-wide studies have additionally identified variation in the foetal gene near Flt-1. The development of preeclampsia is not limited to the maternal interface, but foetal involvement as well as genetic interplay is associated with the disorder.

Mechanotransduction and Uterine Blood Flow in Preeclampsia: The Role of Mechanosensing Piezo 1 Ion Channels

There is a large increase in uterine arterial blood flow during normal pregnancy. Structural and cellular adjustments occur in the uterine vasculature during pregnancy to accommodate this increased blood flow through a complex adaptive process that is dependent on multiple coordinated and interactive influences and this process is known as "vascular remodeling." The etiology of preeclampsia involves aberrant placentation and vascular remodeling leading to reduced uteroplacental perfusion. The placental ischemia leads to development of hypertension and proteinuria in the mother, intrauterine growth restriction, and perinatal death in the fetus. However, the underlying source of the deficient vascular remodeling and the subsequent development of preeclampsia remain to be fully understood. Mechanoreceptors in the vascular system convert mechanical force (shear stress) to biochemical signals and feedback mechanisms. This review focuses on the Piezo 1 channel, a mechanosensitive channel that is sensitive to shear stress in the endothelium; it induces Ca2+ entry which is linked to endothelial nitric oxide synthase (eNOS) activation as the mechanoreceptor responsible for uterine vascular dilatation during pregnancy. Here we describe the downstream signaling pathways involved in this process and the possibility of a deficiency in expression of Piezo 1 in preeclampsia leading to the abnormal vascular dysfunction responsible for the pathophysiology of the disease. The Piezo 1 ion channel is expressed in the endothelium and vascular smooth muscle cells (VSMCs) of small-diameter arteries. It plays a role in the structural remodeling of arteries and is involved in mechanotransduction of hemodynamic shear stress by endothelial cells (ECs).

Role of the NLRP3 Inflammasome in Preeclampsia

Reproduction involves tightly regulated series of events and the immune system is involved in an array of reproductive processes. Disruption of well-controlled immune functions leads to infertility, placental inflammation, and numerous pregnancy complications, including preeclampsia (PE). Inflammasomes are involved in the process of pathogen clearance and sterile inflammation. They are large multi-protein complexes that are located in the cytosol and play key roles in the production of the pivotal inflammatory cytokines, interleukin (IL)-1β and IL-18, and pyroptosis. The nucleotide-binding oligomerization domain, leucine-rich repeat-, and pyrin domain-containing 3 (NLRP3) inflammasome is a key mediator of sterile inflammation induced by various types of damage-associated molecular patterns (DAMPs). Recent evidence indicates that the NLRP3 inflammasome is involved in pregnancy dysfunction, including PE. Many DAMPs (uric acid, palmitic acid, high-mobility group box 1, advanced glycation end products, extracellular vesicles, cell-free DNA, and free fatty acids) are increased and associated with pregnancy complications, especially PE. This review focuses on the role of the NLRP3 inflammasome in the pathophysiology of PE.

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.

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.

Reference centiles for maternal placental growth factor levels at term from a low-risk population

INTRODUCTION

Placental growth factor (PLGF) is a biomarker of placental function. The aim of this study was to define reference ranges for maternal PLGF levels in a normotensive cohort ≥36 + 0 weeks.

METHOD

Prospective observational data from Mater Mothers' Hospital, Brisbane. PLGF levels were measured in women at ≥36 + 0 weeks with singleton, non-anomalous pregnancies. Women with hypertension and fetal growth restriction were excluded. PLGF (pg/mL) was assayed using DELFIA® Xpress (PerkinElmer Inc). The Generalised Additive Model for Location, Shape and Scale (GAMLSS) method was used for the calculation of gestational age-adjusted centiles. Data analysis was performed with Stata 13 (StataCorp, LLC) and R software (R Foundation for Statistical Computing, Vienna, Austria). In all women, PLGF was measured within 2 weeks of delivery.

RESULTS

The study cohort comprised of 845 women (36 weeks n = 73, 37 weeks n = 230, 38 weeks n = 214, 39 weeks n = 172, 40 weeks n = 115, 41weeks n = 41). PLGF levels were negatively correlated with gestational age (r = -0.20, p < 0.001). Median PLGF levels dropped significantly from 36 weeks to 41 weeks (169.0 pg/mL to 96.6 pg/mL, p < 0.001). Gestational age specific maternal PLGF centiles were reported using fractional polynomial additive term and Box-Cox t distribution. PLGF did not perform adequately as a predictive test for adverse perinatal outcomes (AUC <0.6).

DISCUSSION

We have created gestational centile reference ranges for maternal PLGF from a normotensive cohort. These novel data suggest maternal PLGF levels decline ≥36 + 0 weeks. The utility of PLGF as a predictor of adverse perinatal outcomes at term, should be further investigated with clinical trials.

Hormone receptor expression of colorectal cancer diagnosed during the peri-partum period

BACKGROUND

Colorectal carcinoma (CRC) during the peri-partum period is challenging to diagnose due to the overlapping symptoms of CRC and pregnancy. This is the first case series to investigate clinicopathologic, hormonal and molecular features of CRC diagnosed during the peri-partum period. We hypothesized that advanced presentations of CRC could possibly be mitigated by pregnancy-related hormonal factors.

METHODS

We conducted a retrospective review of five women diagnosed with CRC during the peri-partum period and studied the clinical and molecular features of their cancer.

RESULTS

All patients presented with stage IV CRC at diagnosis; three had primary tumors in the rectum and two had primary tumors in the sigmoid colon. The liver was the most common metastatic site (three of five women). Immunohistochemistry stains were negative for estrogen receptors alpha (ERα) and beta (ERβ), and one tumor demonstrated low-level positivity for PR (1%). Formalin-fixed and paraffin-embedded (FFPE) biopsies from each case were tested with next-generation sequencing and found that all tumors were mismatch repair (MMR) proficient, and three harbored a KRAS mutation. Germline testing showed no predisposition to CRC; however, several somatic variants of undetermined significance (VUS) were identified.

DISCUSSION

CRC in the peri-partum period poses significant risk factors for presentations with advanced disease due to diagnostic challenges. While our study provides no evidence that pathogenesis of CRC during pregnancy is driven by elevated estrogen and/or progesterone levels during pregnancy, additional putative etiologic factors, including placental growth factors, the immunosuppressive state of pregnancy and other physiologic processes during pregnancy, warrant future study.

Vascular Endothelial Growth Factor Delivery to Placental Basal Plate Promotes Uterine Artery Remodeling in the Primate

Extravillous trophoblast (EVT) uterine artery remodeling (UAR) promotes placental blood flow, but UAR regulation is unproven. Elevating estradiol (E2) in early baboon pregnancy suppressed UAR and EVT vascular endothelial growth factor (VEGF) expression, but this did not prove that VEGF mediated this process. Therefore, our primate model of prematurely elevating E2 and contrast-enhanced ultrasound cavitation of microbubble (MB) carriers was used to deliver VEGF DNA to the placental basal plate (PBP) to establish the role of VEGF in UAR. Baboons were treated on days 25 to 59 of gestation (term, 184 days) with E2 alone or with E2 plus VEGF DNA-conjugated MBs briefly infused via a maternal peripheral vein on days 25, 35, 45, and 55. At each of these times an ultrasound beam was directed to the PBP to collapse the MBs and release VEGF DNA. VEGF DNA-labeled MBs per contrast agent was localized in the PBP but not the fetus. Remodeling of uterine arteries >25 µm in diameter on day 60 was 75% lower (P < 0.001) in E2-treated (7% ± 2%) than in untreated baboons (30% ± 4%) and was restored to normal by E2/VEGF. VEGF protein levels (signals/nuclear area) within the PBP were twofold lower (P < 0.01) in E2-treated (4.2 ± 0.9) than in untreated (9.8 ± 2.8) baboons and restored to normal by E2/VEGF (11.9 ± 1.6), substantiating VEGF transfection. Thus, VEGF gene delivery selectively to the PBP prevented the decrease in UAR elicited by prematurely elevating E2 levels, establishing the role of VEGF in regulating UAR in vivo during primate pregnancy.

Longitudinal circulating placental growth factor (PlGF) and soluble FMS-like tyrosine kinase-1 (sFlt-1) concentrations during pregnancy in Asian women: a prospective cohort study

OBJECTIVES

To analyse the placental growth factor (PlGF) and soluble FMS-like tyrosine kinase-1 (sFlt-1) trends in the normal pregnant Asian population in Singapore.

DESIGN

A prospective study was conducted.

SETTING

The largest tertiary hospital in Singapore.

METHODS

Women with single viable pregnancies, less than 14 weeks of gestation, were recruited between September 2010 and November 2013 in KK Women's and Children's Hospital. They were followed up from recruitment till their postnatal discharge from the hospital. There were four antenatal visits: gestational age (GA) less than 14+0 weeks of gestation (V1), GA 18+0 to 22+0 weeks (V2), GA 28+0 to 32+0 weeks (V3) and GA 34+0 and above (V4). Serum biochemical markers (sFlt-1, PlGF) were measured at each visit.

RESULTS

There were 934 participants in the study, of which 674 had normal pregnancy outcomes. The sFlt-1 remained relatively constant till GA 28-32 weeks before it increased (p<0.001). The sFlt-1 levels increased earlier before 30 weeks' of gestation among the Malay participants and the other ethnicities. For PlGF, the levels increased from the first to the third trimester, peaking at 30-32 weeks before decreasing (p<0.001). Its serum levels significantly differed among the Indian participants and other ethnicities as compared with the Malay and Chinese participants at V3 and V4, (p=0.04 and p<0.001, respectively).

CONCLUSION

There are significant differences in the PlGF and sFlt-1 concentrations during pregnancy between different ethnicities, which should be taken into consideration when using these references values for further research.

Biochemical tests of placental function versus ultrasound assessment of fetal size for stillbirth and small-for-gestational-age infants

BACKGROUND

Stillbirth affects 2.6 million pregnancies worldwide each year. Whilst the majority of cases occur in low- and middle-income countries, stillbirth remains an important clinical issue for high-income countries (HICs) - with both the UK and the USA reporting rates above the mean for HICs. In HICs, the most frequently reported association with stillbirth is placental dysfunction. Placental dysfunction may be evident clinically as fetal growth restriction (FGR) and small-for-dates infants. It can be caused by placental abruption or hypertensive disorders of pregnancy and many other disorders and factorsPlacental abnormalities are noted in 11% to 65% of stillbirths. Identification of FGA is difficult in utero. Small-for-gestational age (SGA), as assessed after birth, is the most commonly used surrogate measure for this outcome. The degree of SGA is associated with the likelihood of FGR; 30% of infants with a birthweight < 10th centile are thought to be FGR, while 70% of infants with a birthweight < 3rd centile are thought to be FGR. Critically, SGA is the most significant antenatal risk factor for a stillborn infant. Correct identification of SGA infants is associated with a reduction in the perinatal mortality rate. However, currently used tests, such as measurement of symphysis-fundal height, have a low reported sensitivity and specificity for the identification of SGA infants.

OBJECTIVES

The primary objective was to assess and compare the diagnostic accuracy of ultrasound assessment of fetal growth by estimated fetal weight (EFW) and placental biomarkers alone and in any combination used after 24 weeks of pregnancy in the identification of placental dysfunction as evidenced by either stillbirth, or birth of a SGA infant. Secondary objectives were to investigate the effect of clinical and methodological factors on test performance.

SEARCH METHODS

We developed full search strategies with no language or date restrictions. The following sources were searched: MEDLINE, MEDLINE In Process and Embase via Ovid, Cochrane (Wiley) CENTRAL, Science Citation Index (Web of Science), CINAHL (EBSCO) with search strategies adapted for each database as required; ISRCTN Registry, UK Clinical Trials Gateway, WHO International Clinical Trials Portal and ClinicalTrials.gov for ongoing studies; specialist abstract and conference proceeding resources (British Library's ZETOC and Web of Science Conference Proceedings Citation Index). Search last conducted in Ocober 2016.

SELECTION CRITERIA

We included studies of pregnant women of any age with a gestation of at least 24 weeks if relevant outcomes of pregnancy (live birth/stillbirth; SGA infant) were assessed. Studies were included irrespective of whether pregnant women were deemed to be low or high risk for complications or were of mixed populations (low and high risk). Pregnancies complicated by fetal abnormalities and multi-fetal pregnancies were excluded as they have a higher risk of stillbirth from non-placental causes. With regard to biochemical tests, we included assays performed using any technique and at any threshold used to determine test positivity.

DATA COLLECTION AND ANALYSIS

We extracted the numbers of true positive, false positive, false negative, and true negative test results from each study. We assessed risk of bias and applicability using the QUADAS-2 tool. Meta-analyses were performed using the hierarchical summary ROC model to estimate and compare test accuracy.

MAIN RESULTS

We included 91 studies that evaluated seven tests - blood tests for human placental lactogen (hPL), oestriol, placental growth factor (PlGF) and uric acid, ultrasound EFW and placental grading and urinary oestriol - in a total of 175,426 pregnant women, in which 15,471 pregnancies ended in the birth of a small baby and 740 pregnancies which ended in stillbirth. The quality of included studies was variable with most domains at low risk of bias although 59% of studies were deemed to be of unclear risk of bias for the reference standard domain. Fifty-three per cent of studies were of high concern for applicability due to inclusion of only high- or low-risk women.Using all available data for SGA (86 studies; 159,490 pregnancies involving 15,471 SGA infants), there was evidence of a difference in accuracy (P < 0.0001) between the seven tests for detecting pregnancies that are SGA at birth. Ultrasound EFW was the most accurate test for detecting SGA at birth with a diagnostic odds ratio (DOR) of 21.3 (95% CI 13.1 to 34.6); hPL was the most accurate biochemical test with a DOR of 4.78 (95% CI 3.21 to 7.13). In a hypothetical cohort of 1000 pregnant women, at the median specificity of 0.88 and median prevalence of 19%, EFW, hPL, oestriol, urinary oestriol, uric acid, PlGF and placental grading will miss 50 (95% CI 32 to 68), 116 (97 to 133), 124 (108 to 137), 127 (95 to 152), 139 (118 to 154), 144 (118 to 161), and 144 (122 to 161) SGA infants, respectively. For the detection of pregnancies ending in stillbirth (21 studies; 100,687 pregnancies involving 740 stillbirths), in an indirect comparison of the four biochemical tests, PlGF was the most accurate test with a DOR of 49.2 (95% CI 12.7 to 191). In a hypothetical cohort of 1000 pregnant women, at the median specificity of 0.78 and median prevalence of 1.7%, PlGF, hPL, urinary oestriol and uric acid will miss 2 (95% CI 0 to 4), 4 (2 to 8), 6 (6 to 7) and 8 (3 to 13) stillbirths, respectively. No studies assessed the accuracy of ultrasound EFW for detection of pregnancy ending in stillbirth.

AUTHORS' CONCLUSIONS

Biochemical markers of placental dysfunction used alone have insufficient accuracy to identify pregnancies ending in SGA or stillbirth. Studies combining U and placental biomarkers are needed to determine whether this approach improves diagnostic accuracy over the use of ultrasound estimation of fetal size or biochemical markers of placental dysfunction used alone. Many of the studies included in this review were carried out between 1974 and 2016. Studies of placental substances were mostly carried out before 1991 and after 2013; earlier studies may not reflect developments in test technology.