Angiogenic factors at diagnosis of late-onset small-for-gestational age and histological placental underperfusion

Does the use of angiogenic biomarkers for the management of preeclampsia and fetal growth restriction improve outcomes?: Challenging the current status quo

Monitoring and timing of delivery in preterm preeclampsia and fetal growth restriction is one of the biggest challenges in Obstetrics. Finding the optimal time of delivery of these fetuses usually involves a trade-off between the severity of the disease and prematurity. So far, most clinical guidelines recommend the use of a combination between clinical, laboratory and ultrasound markers to guide the time of delivery. Angiogenic biomarkers, especially placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1), have gained significant attention in recent years for their potential role in the prediction and diagnosis of placenta-related disorders including preeclampsia and fetal growth restriction. Another potential clinical application of the angiogenic biomarkers is for the differential diagnosis of patients with chronic kidney disease, as this condition shares similar clinical features with preeclampsia. Consequently, angiogenic biomarkers have been advocated as tools for monitoring and deciding the optimal time of the delivery of fetuses affected by placental dysfunction. In this clinical opinion, we critically review the available literature on PlGF and sFlt-1 for the surveillance and time of the delivery in fetuses affected by preterm preeclampsia and fetal growth restriction. Moreover, we explore the use of angiogenic biomarkers for the differentiation between chronic kidney disease and superimposed preeclampsia.

The role of the PLGF in the prediction of the outcome in pregnancies with a small for gestational age fetus

PURPOSE

To explore the value of measuring maternal serum PLGF in the prediction of the outcome of small for gestational age fetuses (SGA).

METHODS

Singleton pregnancies referred with suspicion of SGA in the third trimester were included if they had: no indication for nor signs of imminent delivery, fetal abdominal circumference (AC) at or below the 10th centile and/or estimated fetal weight (EFW) at or below the 10th centile and/or umbilical artery pulsatility index (Umb-PI) at or above the 90th centile for gestation. Women with pre-eclampsia at presentation were excluded. Maternal blood was drawn at the first (index) visit and analyzed retrospectively.

RESULTS

Fifty-one fetuses were examined. Multiple regression analysis showed that family history of microsomia, index EFW and PLGF were significant predictors of the birthweight centile; index femur length centile and PLGF were significant predictors of pre-eclampsia; PLGF and index systolic blood pressure were significant predictors of iatrogenic preterm delivery < 37 weeks, whereas PLGF and index EFW were significant predictors of birthweight ≤ 5th centile and admission to the neonatal intensive care unit. For all outcomes, the addition of maternal-fetal parameters did not improve the prediction compared to PLGF alone. Using a cutoff of 0.3 MoM for PLGF would identify 94.1% of the pregnancies with iatrogenic preterm delivery and/or intra-uterine death and all of the cases that developed pre-eclampsia, for a screen positive rate of 54.9%. Women with PLGF ≤ 0.3 MoM had a poor fetal/maternal outcome (iatrogenic preterm delivery, pre-eclampsia, intra-uterine death) in 61.5% of cases.

CONCLUSION

In pregnancies complicated by SGA, PLGF identifies a very high-risk group that may benefit from intense surveillance.

Early Fetal Growth Restriction with or Without Hypertensive Disorders: a Clinical Overview

Early onset fetal growth restriction (FGR) is one of the main adverse pregnancy conditions, often associated with poor neonatal outcomes. Frequently, early onset FGR is associated with early onset hypertensive disorders of pregnancy (HDP), and in particular preeclampsia (PE). However, to date, it is still an open question whether pregnancies complicated by early FGR plus HDP (FGR-HDP) and those complicated by early onset FGR without HDP (normotensive-FGR (n-FGR)) show different prenatal and postnatal outcomes and, consequently, should benefit from different management and long-term follow-up. Recent data support the hypothesis that the presence of PE may have an additional impact on maternal hemodynamic impairment and placental lesions, increasing the risk of poor neonatal outcomes in pregnancy affected by early onset FGR-HDP compared to pregnancy affected by early onset n-FGR. This review aims to elucidate this poor studied topic, comparing the clinical characteristics, perinatal outcomes, and potential long-term sequelae of early onset FGR-HDP and early onset n-FGR.

The association between human chorionic gonadotropin and adverse pregnancy outcomes: a systematic review and meta-analysis

OBJECTIVE

This study aimed to evaluate the association between human chorionic gonadotropin and adverse pregnancy outcomes.

DATA SOURCES

Medline, Embase, PubMed, and Cochrane were searched in November 2021 using Medical Subject Headings (MeSH) and relevant key words.

STUDY ELIGIBILITY CRITERIA

This analysis included published full-text studies of pregnant women with serum human chorionic gonadotropin testing between 8 and 28 weeks of gestation, investigating fetal outcomes (fetal death in utero, small for gestational age, preterm birth) or maternal factors (hypertension in pregnancy: preeclampsia, pregnancy-induced hypertension, placental abruption, HELLP syndrome, gestational diabetes mellitus).

METHODS

Studies were extracted using REDCap software. The Newcastle-Ottawa scale was used to assess for risk of bias. Final meta-analyses underwent further quality assessment using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) method.

RESULTS

A total of 185 studies were included in the final review, including the outcomes of fetal death in utero (45), small for gestational age (79), preterm delivery (62), hypertension in pregnancy (107), gestational diabetes mellitus (29), placental abruption (17), and HELLP syndrome (2). Data were analyzed separately on the basis of categorical measurement of human chorionic gonadotropin and human chorionic gonadotropin measured on a continuous scale. Eligible studies underwent meta-analysis to generate a pooled odds ratio (categorical human chorionic gonadotropin level) or difference in medians (human chorionic gonadotropin continuous scale) between outcome groups. First-trimester low human chorionic gonadotropin levels were associated with preeclampsia and fetal death in utero, whereas high human chorionic gonadotropin levels were associated with preeclampsia. Second-trimester high human chorionic gonadotropin levels were associated with fetal death in utero and preeclampsia.

CONCLUSION

Human chorionic gonadotropin levels are associated with placenta-mediated adverse pregnancy outcomes. Both high and low human chorionic gonadotropin levels in the first trimester of pregnancy can be early warning signs of adverse outcomes. Further analysis of human chorionic gonadotropin subtypes and pregnancy outcomes is required to determine the diagnostic utility of these findings in reference to specific cutoff values.

Usefulness of angiogenic factors in prenatal counseling of late-onset fetal growth-restricted and small-for-gestational-age gestations: a prospective observational study

OBJECTIVES

To create a predictive model including biomarkers and evaluate its ability to predict adverse perinatal outcomes in late-onset small fetuses, ultimately helping to provide individualized counseling at the time of diagnosis.

METHODS

This was a prospective observational study, including singleton pregnancies with an estimated fetal weight (EFW) below the 10th percentile, at a gestational age between 32 + 0 and 36 + 6 weeks of gestation (WG). Variables recorded at diagnosis to predict adverse pregnancy outcomes were: soluble fms-like tyrosine-kinase-1 to placental growth factor ratio (sFlt-1/PlGF), fetal Doppler (umbilical artery and middle cerebral artery), uterine artery pulsatility index (UtAPI), EFW percentile, gestational age, and the presence of maternal risk factors for placental insufficiency. Logistic regression models were developed for the prediction of three co-primary outcomes: composite adverse perinatal outcomes (APO), and the need for elective delivery before 35 or 37 WG.

RESULTS

Sixty (52.2%) fetal growth restricted (FGR) and 55 (47.8%) small for gestational age (SGA) were enrolled. Thirteen (11.3%) women needed elective delivery before 35 WG and 27 (23.5%) women before 37 WG. At least one APO occurred in 43 (37.4%) pregnancies. The best marker in univariate analyses was the sFlt-1/PlGF ratio [AUC = 0.932 (95% CI, 0.864-0.999)]. The multivariate model including sFlt-1/PlGF showed a better predictive performance for APO than the multivariate model without sFlt-1/PlGF (P < 0.024).

CONCLUSIONS

sFlt-1/PlGF is a good predictor of APO at the time of late-onset FGR/SGA diagnosis. Our predictive models may be useful to provide early individualized prenatal counseling in this group of women. Further studies are needed to validate these preliminary findings in a larger cohort.

Third-trimester uterine artery Doppler for prediction of adverse outcome in late small-and adequate for-gestational-age fetuses

Fetal growth restriction includes all those fetuses that do not reach their own growth potential due to placental insufficiency and therefore at higher risk of adverse perinatal outcomes. Identification and follow-up of these fetuses is essential to decrease this additional risk. Although estimated fetal weight under the 3rd centile and pathological cerebroplacental ratio are the most accepted predictive criteria, some evidence suggests that abnormal uterine artery Doppler may be a useful prognostic parameter in late-onset growth restriction fetuses at the moment of diagnosis. However, its prediction capacity as a standalone parameter is limited. In that context, integrated models of biometric and hemodynamic ultrasound parameters including uterine Doppler have been proposed as an effective approach to stratify the risk and improve perinatal outcomes. Moreover, an association of abnormal uterine artery Doppler and histological findings of placental underperfusion due to vascular obstruction has been described. Finally, it has also been suggested that the evaluation of uterine artery Doppler at third trimester in appropriate-for-gestational-age fetuses could identify cases of subclinical placental insufficiency, but further evidence is needed to define such predictive strategies.

Maternal PlGF and umbilical Dopplers predict pregnancy outcomes at diagnosis of early-onset fetal growth restriction

BACKGROUNDSevere, early-onset fetal growth restriction (FGR) causes significant fetal and neonatal mortality and morbidity. Predicting the outcome of affected pregnancies at the time of diagnosis is difficult, thus preventing accurate patient counseling. We investigated the use of maternal serum protein and ultrasound measurements at diagnosis to predict fetal or neonatal death and 3 secondary outcomes: fetal death or delivery at or before 28+0 weeks, development of abnormal umbilical artery (UmA) Doppler velocimetry, and slow fetal growth.METHODSWomen with singleton pregnancies (n = 142, estimated fetal weights [EFWs] below the third centile, less than 600 g, 20+0 to 26+6 weeks of gestation, no known chromosomal, genetic, or major structural abnormalities) were recruited from 4 European centers. Maternal serum from the discovery set (n = 63) was analyzed for 7 proteins linked to angiogenesis, 90 additional proteins associated with cardiovascular disease, and 5 proteins identified through pooled liquid chromatography and tandem mass spectrometry. Patient and clinician stakeholder priorities were used to select models tested in the validation set (n = 60), with final models calculated from combined data.RESULTSThe most discriminative model for fetal or neonatal death included the EFW z score (Hadlock 3 formula/Marsal chart), gestational age, and UmA Doppler category (AUC, 0.91; 95% CI, 0.86-0.97) but was less well calibrated than the model containing only the EFW z score (Hadlock 3/Marsal). The most discriminative model for fetal death or delivery at or before 28+0 weeks included maternal serum placental growth factor (PlGF) concentration and UmA Doppler category (AUC, 0.89; 95% CI, 0.83-0.94).CONCLUSIONUltrasound measurements and maternal serum PlGF concentration at diagnosis of severe, early-onset FGR predicted pregnancy outcomes of importance to patients and clinicians.TRIAL REGISTRATIONClinicalTrials.gov NCT02097667.FUNDINGThe European Union, Rosetrees Trust, Mitchell Charitable Trust.

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.

Management of fetal Growth Restriction at term by Angiogenic Factors versus feto-maternal Doppler (GRAFD) to avoid adverse perinatal outcomes: multicenter open-label randomized controlled trial study protocol (Preprint)

Background

Fetal smallness affects 10% of pregnancies. Small fetuses are at a higher risk of adverse outcomes. Their management using estimated fetal weight and feto-maternal Doppler has a high sensitivity for adverse outcomes; however, more than 60% of fetuses are electively delivered at 37 to 38 weeks. On the other hand, classification using angiogenic factors seems to have a lower false-positive rate. Here, we present a protocol for the Fetal Growth Restriction at Term Managed by Angiogenic Factors Versus Feto-Maternal Doppler (GRAFD) trial, which compares the use of angiogenic factors and Doppler to manage small fetuses at term.

Objective

The primary objective is to demonstrate that classification based on angiogenic factors is not inferior to estimated fetal weight and Doppler at detecting fetuses at risk of adverse perinatal outcomes.

Methods

This is a multicenter, open-label, randomized controlled trial conducted in 20 hospitals across Spain. A total of 1030 singleton pregnancies with an estimated fetal weight ≤10th percentile at 36+0 to 37+6 weeks+days will be recruited and randomly allocated to either the control or the intervention group. In the control group, standard Doppler-based management will be used. In the intervention group, cases with a soluble fms-like tyrosine kinase to placental growth factor ratio ≥38 will be classified as having fetal growth restriction; otherwise, they will be classified as being small for gestational age. In both arms, the fetal growth restriction group will be delivered at ≥37 weeks and the small for gestational age group at ≥40 weeks. We will assess differences between the groups by calculating the relative risk, the absolute difference between incidences, and their 95% CIs.

Results

Recruitment for this study started on September 28, 2020. The study results are expected to be published in peer-reviewed journals and disseminated at international conferences in early 2023.

Conclusions

The angiogenic factor–based protocol may reduce the number of pregnancies classified as having fetal growth restriction without worsening perinatal outcomes. Moreover, reducing the number of unnecessary labor inductions would reduce costs and the risks derived from possible iatrogenic complications. Additionally, fewer inductions would lower the rate of early-term neonates, thus improving neonatal outcomes and potentially reducing long-term infant morbidities.

Trial Registration

ClinicalTrials.gov NCT04502823; https://clinicaltrials.gov/ct2/show/NCT04502823

International Registered Report Identifier (IRRID)

DERR1-10.2196/37452

The Role of High Concentrations of Homocysteine for the Development of Fetal Growth Restriction

OBJECTIVE

 To assess homocysteine (Hcy) levels in the three trimesters of pregnancy in women with fetal growth restriction (FGR) and to evaluate the role of Hcy as a possible predictor of FGR.

METHODS

 A total of 315 singleton pregnant women were included in the present prospective cohort study and were monitored since the 1^st trimester of pregnancy before delivery. Newborns were monitored for the first 7 days of life. Patients who had risk factors for FGR were excluded. Fetal growth restriction was defined according to uterine fundal height (< 10 percentile), ultrasound fetometry (< 5 percentile), and anthropometry of newborns (< 5 percentile). The concentrations of Hcy were detected at between 10 and 14, between 20 and 24, and between 30 and 34 weeks of pregnancy by enzyme-linked immunosorbent assay (ELISA). Receiver operating characteristics (ROC) curve test and diagnostic odds ratio (DOR) were performed to evaluate the results of ELISA.

RESULTS

 The concentration of Hcy in patients with FGR was 19.65 umol/L at between 10 and 14 weeks, compared with 9.28 umol/L in patients with normal fetal growth (p < 0.0001). The optimal cut-off level for Hcy in the 1^st trimester of pregnancy was > 13.9 umol/L with AUC 0.788, sensitivity of 75%, specificity of 83.6%, and DOR of 15.2.

CONCLUSION

 Assessment of serum Hcy concentration may be used as a predictor of FGR, with the highest diagnostic utility in the 1^st trimester of pregnancy.

Association between fetoplacental Doppler results, placental pathology, and angiogenic factors among pregnant women with anxiety

OBJECTIVE

This study aimed to evaluate whether state and trait anxiety among pregnant women were associated with fetoplacental Doppler findings, abnormal placental pathology, and placental angiogenic factors.

MATERIALS AND METHODS

A total of 102 pregnant women at 32-35 gestational weeks were recruited and examined prospectively. State and trait anxiety were measured using the State-Trait Anxiety Inventory. Using Doppler ultrasound, pulsatility index (PI) of the umbilical artery (UA), middle cerebral artery (MCA), and uterine artery (UtA) and cerebroplacental ratio (CPR) were determined. Doppler parameters were converted into multiples of the median (MoM). Abnormal placental pathology was classified into 2 groups: vascular underperfusion (VU) and histological chorioamnionitis (HCA). Immunohistochemical analysis was performed to examine placental cells staining positive for placental growth factor (PLGF) and hypoxia-inducible factor-1-α (HIF-1α), which are markers for angiogenesis and hypoxic status, respectively.

RESULTS

Women with high state anxiety scores had low MCA-PI MoM and CPR MoM, while those with high trait anxiety scores had low MCA-PI MoM. VU was associated with a higher incidence of high trait anxiety scores, and HCA was associated with a higher incidence of high state and trait anxiety scores. Regression analysis showed a relationship between maternal state anxiety on MCA-PI MoM and HCA after controlling for covariates. Maternal trait anxiety exhibited relationships with VU and HCA after adjustment.

CONCLUSION

Our results demonstrated that maternal anxiety is associated with altered fetal cerebral blood flow and abnormal placental pathology but is not associated with uteroplacental insufficiency and placental angiogenic factors.

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

INTRODUCTION

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

MATERIAL AND METHODS

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

RESULTS

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

DISCUSSION

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

How to define late fetal growth restriction

A fraction of third-trimester small fetuses does not achieve their endowed growth potential mainly due to placental insufficiency, usually not evident in terms of impaired umbilical artery Doppler, but severe enough to increase the risk of perinatal adverse outcomes and long-term complications. The identification of those fetuses at higher-risk helps to optimize their follow-up and to decrease the risk of intrauterine demise. Several parameters can help in the identification of those fetuses at higher risk, defined as fetal growth restricted (FGR) fetuses. Severe smallness and the cerebroplacental ratio are the most consistent parameters; regarding uterine artery Doppler, although some evidence in favour has been published, there is currently no consensus about its use. Thirty-two weeks of gestation is the accepted cut-off to define late FGR. The differentiation with early FGR is necessary as these two entities have different clinical maternal manifestations, and different associated short-term and long-term neonatal outcomes. The use of angiogenic factors is promising but more research is needed on this field.

Placental Lesions and Pregnancy Outcome in Anterior as Compared to Posterior Placenta Previa

The uterine location of placenta previa (PP), anterior vs. posterior has an impact on pregnancy outcome. We aimed to study maternal and neonatal outcome and placental histopathology lesions in anterior vs. posterior PP. The medical records and histopathology reports of all singleton cesarean deliveries (CD) performed due to PP, from 24 to 41 weeks, between 12.2008 and 10.2018, were reviewed. Placental lesions were classified into maternal and fetal vascular malperfusion lesions (MVM, FVM), maternal and fetal inflammatory responses (MIR, FIR). Gestational age (GA) at delivery was similar between the anterior PP (n = 67) and posterior PP (n = 105) groups. As compared to the posterior PP group, the anterior PP group had higher rate of previous CD (p < 0.001), placental accreta spectrum (p = 0.04), lower neonatal Hb at birth (p = 0.03), higher rate of neonatal blood transfusion (p = 0.007) and prolonged maternal hospitalization (p = 0.02). Placentas from the anterior PP group had lower weights (p = 0.035), with increased rate of MVM lesions (p = 0.017). The anterior PP location is associated with increased adverse maternal and neonatal outcome, lower placental weights and increased rate of malperfusion lesions. Abnormal placentation in the scarred uterine wall probably has an impact on placental function.

Doppler studies of placental function

Placental-associated diseases account for most cases of adverse perinatal outcome in developing countries. Doppler evaluation has been incorporated as a predictive parameter at early pregnancy for high-risk placental disease, in the diagnosis and management of those fetuses with impaired intrauterine growth and for the evaluation of fetal wellbeing in those high-risk pregnancies. Uterine Doppler at second trimester predicts most instances of early-onset preeclampsia and intrauterine growth restriction. However, the growing evidence of an effective early propylactic strategy, has turned Uterine Doppler an essential parameter to be included in first trimester predictive algorithms. Umbilical artery Doppler helps in the identification of small-for-gestational-age fetuses at higher risk, and is one of the essential vessels in the assessment of fetal hypoxia impairment, especially in the early cases. It helps in the decision timing for ending the pregnancy improving thus perinatal outcomes. Moreover, in high-risk pregnancies, umbilical artery Doppler has demonstrated to reduce the risk of perinatal deaths and the risk of obstetric interventions. On the other hand, middle cerebral artery Doppler reflects fetal adaptation to hypoxia, and with the cerebroplacental ratio, they improve the detection of fetuses a high risk of adverse perinatal outcome, mostly of those late small fetuses, where most instances of adverse outcome occur in fetuses with normal umbilical artery. Ductus venosous Doppler waveform is a surrogate parameter of the fetal base-acid status. Its use has demonstrated to improve perinatal outcomes, mainly reducing the risk of fetal intrauterine death. Alone or in combination with computerized CTG, it helps tailoring the best moment to end the pregnancy among early cases.

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.

The PLANES study: a protocol for a randomised controlled feasibility study of the placental growth factor (PlGF) blood test-informed care versus standard care alone for women with a small for gestational age fetus at or after 32 + 0 weeks' gestation

Background

Stillbirth remains a major concern across the globe and in some high-resource countries, such as the UK; efforts to reduce the rate have achieved only modest reductions. One third of stillborn babies are small for gestational age (SGA), and these pregnancies are also at risk of neonatal adverse outcomes and lifelong health problems, especially when delivered preterm. Current UK clinical guidance advocates regular monitoring and early term delivery of the SGA fetus; however, the most appropriate regimen for surveillance of these babies remains unclear and often leads to increased intervention for a large number of these women. This pilot trial will determine the feasibility of a large-scale trial refining the risk of adverse pregnancy outcome in SGA pregnancies using biomarkers of placental function sFlt-1/PlGF, identifying and intervening in only those deemed at highest risk of stillbirth.

Methods

PLANES is a randomised controlled feasibility study of women with an SGA fetus that will be conducted at two tertiary care hospitals in the UK. Once identified on ultrasound, women will be randomised into two groups in a 3:1 ratio in favour of sFlt-1/PlGF ratio led management vs standard care. Women with an SGA fetus and a normal sFlt-1/PlGF ratio will have a repeat ultrasound and sFlt-1/PlGF ratio every 2 weeks with planned birth delayed until 40 weeks. In those women with an SGA fetus and an abnormal sFlt-1/PlGF ratio, we will offer birth from 37 weeks or sooner if there are other concerning features on ultrasound. Women assigned to standard care will have an sFlt-1/PlGF ratio taken, but the results will be concealed from the clinical team, and the woman’s pregnancy will be managed as per the local NHS hospital policy. This integrated mixed method study will also involve a health economic analysis and a perspective work package exploring trial feasibility through interviews and questionnaires with participants, their partners, and clinicians.

Discussion

Our aim is to determine feasibility through the assessment of our ability to recruit and retain participants to the study. Results from this pilot study will inform the design of a future large randomised controlled trial that will be adequately powered for adverse pregnancy outcome. Such a study would provide the evidence needed to guide future management of the SGA fetus.

Trial registration

ISRCTN58254381. Registered on 4 July 2019

"Screening for small-for-gestational age neonates at early third trimester in a high-risk population for preeclampsia"

BACKGROUND

Strategies to improve prenatal detection of small-for-gestational age (SGA) neonates are necessary because its association with poorer perinatal outcome. This study evaluated, in pregnancies with first trimester high risk of early preeclampsia, the performance of a third trimester screening for SGA combining biophysical and biochemical markers.

METHODS

This is a prospective longitudinal study on 378 singleton pregnancies identified at high risk of early preeclampsia according to a first trimester multiparametric algorithm with the cutoff corresponding to 15% false positive rate. This cohort included 50 cases that delivered SGA neonates with birthweight < 10th centile (13.2%) and 328 cases with normal birthweight (86.8%). At 27-30 weeks' gestation, maternal weight, blood pressure, estimated fetal weight, mean uterine artery pulsatility index and maternal biochemical markers (placental growth factor and soluble FMS-Like Tyrosine Kinase-1) were assessed. Different predictive models were created to evaluate their performance to predict SGA neonates.

RESULTS

For a 15% FPR, a model that combines maternal characteristics, estimated fetal weight, mean uterine artery pulsatility index and placental growth factor achieved a detection rate (DR) of 56% with a negative predictive value of 92.2%. The area under receiver operating characteristic curve (AUC) was 0.79 (95% confidence interval (CI), 0.72-0.86). The DR of a model including maternal characteristics, estimated fetal weight and mean uterine artery pulsatility index was 54% (AUC, 0.77 (95% CI, 0.70-0.84)). The DR of a model that includes maternal characteristics and placental growth factor achieved a similar performance (DR 56%, AUC 0.75, 95% CI (0.67-0.83)).

CONCLUSIONS

The performance of screening for SGA neonates at early third trimester combining biophysical and biochemical markers in a high-risk population is poor. However, a high negative predictive value could help in reducing maternal anxiety, avoid iatrogenic interventions and propose a specific plan for higher risk patients.

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

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

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.

Placental growth factor as a predictive marker of preeclampsia - PREBIO study - PREeclampsia BIOchemical study

INTRODUCTION

To evaluate the clinical utility of placental growth factor (PlGF) for the prediction of preeclampsia (PE).

MATERIALS AND METHODS

This prospective cohort study included women divided into three groups: (1) pregnancies without preconceptional risk of developing PE; (2) pregnancies with a preconceptional and/or current risk of developing PE; (3) PE-complicated pregnancies (control group). Blood samples were collected every 4-5 weeks or during hospitalization from early second trimester until delivery in the group 1 and 2, at the diagnosis of PE in the group 3. Plasma levels of PlGF were measured using The Triage PlGF test (Alere) and considered pathological under the 5th centile for gestational age. Sensitivity (Sn), specificity (Sp), positive and negative predictive value (PPV, NPV) were calculated.

RESULTS

In group 1, 30% of women (3/10) had pathological test but none of them developed PE (Sp 70%, NPV 100%). In group 2 (n = 75), none of the patients with normal test developed PE (0/24), while 39% of women with PlGF < 5th centile (20/51) developed PE (Sn 100%, Sp 44%, PPV 39%, NPV 100%). In group 3 (n = 11) all women except one had a pathological PlGF test (Sn 90%, PPV 100%).

CONCLUSIONS

Our data support recent studies which identify PlGF as a biochemical marker not only of PE, but also of placental dysfunction. In fact, it is useful for ruling out PE in women at risk because of the high Sn and high NPV: a normal PlGF is related with a positive pregnancy outcome. Therefore, the measurement of this biomarker would simplify PE clinical management and would reduce costs.

Distinctive patterns of placental lesions in pre-eclampsia vs small-for-gestational age and their association with fetoplacental Doppler

OBJECTIVES

To describe placental histopathological findings in a large cohort of pregnancies complicated by pre-eclampsia (PE) and/or small-for-gestational age (SGA), and to investigate their association with fetoplacental Doppler parameters.

METHODS

This was a prospective observational study of normotensive pregnancies with SGA (defined as birth weight < 10^th centile) (n = 184), PE pregnancies with a normally grown fetus (n = 102), pregnancies with both PE and SGA (n = 120) and uncomplicated pregnancies (n = 202). Uterine (UtA), umbilical (UA) and fetal middle cerebral (MCA) artery pulsatility indices (PI) were assessed. The cerebroplacental ratio (CPR) was calculated by dividing MCA-PI by UA-PI. Doppler parameters were considered abnormal when UtA-PI or UA-PI was > 95^th centile or MCA-PI or CPR was < 5^th centile. Placental lesions were categorized as vascular (maternal or fetal side), immunoinflammatory or other, according to the 2014 Amsterdam Placental Workshop Group Consensus Statement. Comparison between the study groups was performed using univariate and multiple regression analysis, and logistic regression was used to determine the relationship between abnormal Doppler parameters and placental lesions.

RESULTS

Maternal-side vascular lesions were significantly more common in PE pregnancies with SGA than in the other groups (PE + SGA, 73% vs PE, 46% vs SGA, 38% vs controls, 31%; P = 0.01) and included mainly two types of lesion: developmental (PE + SGA, 13% vs PE, 5% vs SGA, 3% vs controls, 1.5%; P < 0.001) and malperfusion (PE + SGA, 70% vs PE, 39% vs SGA, 32% vs controls, 25%; P = 0.001). In contrast, the incidence of fetal-side developmental lesions was significantly higher in normotensive SGA pregnancies than in controls and PE pregnancies (PE + SGA, 0% vs PE, 3% vs SGA, 8% vs controls, 2%; P = 0.001). All cases displayed a lower prevalence of infectious lesions than did controls, with the highest prevalence of immune lesions observed in pregnancies with both PE and SGA (PE + SGA, 18% vs PE, 8% vs SGA, 10% vs controls, 9%; P = 0.001). All fetoplacental Doppler parameters evaluated were associated with maternal-side vascular lesions, mainly malperfusion (mean UtA-PI: odds ratio (OR), 2.45 (95% CI, 1.51-3.97); UA-PI: OR, 2.05 (95% CI, 1.02-4.47); MCA-PI: OR, 2.75 (95% CI, 1.40-5.42); CPR: OR, 1.75 (95% CI, 1.04-2.95)). This association was evident mainly in the normotensive SGA group, being non-significant in controls or PE pregnancies without SGA. No significant associations were observed between fetoplacental Doppler parameters and other placental lesions in any of the study groups.

CONCLUSIONS

PE and SGA are associated with different patterns of placental histopathological lesions in accordance with the clinical manifestation of the placental disorder (maternal vs fetal). Fetoplacental Doppler findings show an association with placental malperfusion lesions on the maternal side, supporting the use of abnormal Doppler as a surrogate for placental insufficiency. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Perspective: L-arginine and L-citrulline Supplementation in Pregnancy: A Potential Strategy to Improve Birth Outcomes in Low-Resource Settings

The available data support the hypothesis that L-arginine or L-citrulline supplementation would be suitable for implementation in resource-constrained settings and will enhance placental vascular development and improve birth outcomes. In resource-constrained settings, the rates of adverse birth outcomes, including fetal growth restriction, preterm birth, and low birth weight, are disproportionately high. Complications resulting from preterm birth are now the leading cause of mortality in children <5 y of age worldwide. Despite the global health burden of adverse birth outcomes, few effective interventions are currently available and new strategies are urgently needed, especially for low-resource settings. L-arginine is a nutritionally essential amino acid in pregnancy and an immediate precursor of nitric oxide. During pregnancy, placental and embryonic growth increases the demand for L-arginine, which can exceed endogenous synthesis of L-arginine from L-citrulline, necessitating increased dietary intake. In many low-resource settings, dietary intake of L-arginine in pregnancy is inadequate owing to widespread protein malnutrition and depletion of endogenous L-arginine due to maternal infections, in particular malaria. Here we examine the role of the L-arginine-nitric oxide biosynthetic pathway in pregnancy including placental vascular development and fetal growth. We review the evidence for the relations between altered L-arginine bioavailability and pregnancy outcomes, and strategies for arginine supplementation in pregnancy. Existing studies of L-arginine supplementation in pregnancy in high-resource settings have shown improved maternal and fetal hemodynamics, prevention of pre-eclampsia, and improved birth outcomes including higher birth weight and longer gestation. Arginine supplementation studies now need to be extended to pregnant women in low-resource settings, especially those at risk of malaria.

Fetal Growth Restriction Prediction: How to Move beyond

The actual burden and future burden of the small-for-gestational-age (SGA) babies turn their screening in pregnancy a question of major concern for clinicians and policymakers. Half of stillbirths are due to growth restriction in utero, and possibly, a quarter of livebirths of low- and middle-income countries are SGA. Growing body of evidence shows their higher risk of adverse outcomes at any period of life, including increased rates of neurologic delay, noncommunicable chronic diseases (central obesity and metabolic syndrome), and mortality. Although there is no consensus regarding its definition, birthweight centile threshold, or follow-up, we believe birthweight <10th centile is the most suitable cutoff for clinical and epidemiological purposes. Maternal clinical factors have modest predictive accuracy; being born SGA appears to be of transgenerational heredity. Addition of ultrasound parameters improves prediction models, especially using estimated fetal weight and abdominal circumference in the 3rd trimester of pregnancy. Placental growth factor levels are decreased in SGA pregnancies, and it is the most promising biomarker in differentiating angiogenesis-related SGA from other causes. Unfortunately, however, only few societies recommend universal screening. SGA evaluation is the first step of a multidimensional approach, which includes adequate management and long-term follow-up of these newborns. Apart from only meliorating perinatal outcomes, we hypothesize SGA screening is a key for socioeconomic progress.

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.

Assessing the sensitivity of placental growth factor and soluble fms-like tyrosine kinase 1 at 36 weeks' gestation to predict small-for-gestational-age infants or late-onset preeclampsia: a prospective nested case-control study

Background

Fetal growth restriction is a disorder of placental dysfunction with three to four-fold increased risk of stillbirth. Fetal growth restriction has pathophysiological features in common with preeclampsia. We hypothesised that angiogenesis-related factors in maternal plasma, known to predict preeclampsia, may also detect fetal growth restriction at 36 weeks’ gestation. We therefore set out to determine the diagnostic performance of soluble fms-like tyrosine kinase 1 (sFlt-1), placental growth factor (PlGF), and the sFlt-1:PlGF ratio, measured at 36 weeks’ gestation, in identifying women who subsequently give birth to small-for-gestational-age (SGA; birthweight <10th centile) infants. We also aimed to validate the predictive performance of the analytes for late-onset preeclampsia in a large independent, prospective cohort.

Methods

A nested 1:2 case-control study was performed including 102 cases of SGA infants and a matched group of 207 controls; and 39 cases of preeclampsia. We determined the diagnostic performance of each angiogenesis-related factor, and of their ratio, to detect SGA infants or preeclampsia, for a predetermined 10% false positive rate.

Results

Median plasma levels of PlGF at 36 weeks’ gestation were significantly lower in women who subsequently had SGA newborns (178.5 pg/ml) compared to normal birthweight controls (326.7 pg/ml, p < 0.0001). sFlt-1 was also higher among SGA cases, but this was not significant after women with concurrent preeclampsia were excluded. The sensitivity of PlGF to predict SGA infants was 28.8% for a 10% false positive rate. The sFlt-1:PlGF ratio demonstrated better sensitivity for preeclampsia than either analyte alone, detecting 69.2% of cases for a 10% false positive rate.

Conclusions

Plasma PlGF at 36 weeks’ gestation is significantly lower in women who subsequently deliver a SGA infant. While the sensitivity and specificity of PlGF currently limit clinical translation, our findings support a blood-based biomarker approach to detect late-onset fetal growth restriction. Thirty-six week sFlt-1:PlGF ratio predicts 69.2% of preeclampsia cases, and could be a useful screening test to triage antenatal surveillance.

Electronic supplementary material

The online version of this article (10.1186/s12884-018-1992-x) contains supplementary material, which is available to authorized users.

sFlt-1/PlGF and Doppler ultrasound parameters in SGA pregnancies with confirmed neonatal birth weight below 10th percentile

We explored whether there was a relationship between the sFlt-1/PlGF ratio in early-late and late-onset SGA patients and whether it is associated with neonatal birth weight.

MATERIAL/METHODS

110 patients who were diagnosed with a fetal weight below the 10th percentile for gestational age and who at the same time delivered neonates with a birth weight below the 10th percentile for gestational age. For each of the patients sFlt-1, PlGF and the sFlt-1/PlGF ratio were studied and uterine artery (UtA) and umbilical artery (UA) Doppler were performed.

RESULTS

sFlt-1/PlGF ratios and neonatal birth weight which showed significant negative correlation across the entire population studied (R = -0.46, p < 0.001). In late-onset SGA patients this negative correlation was observed, as well (R = -0.54, p < 0.001) In the group of patients with pregnancies older than 34 weeks and an sFlt-1/PlGF ratio ≥38, we observed a significantly lower neonatal birth weight when compared to the same gestational age group with an sFlt-1/PlGF ratio <38 (2045 g vs 2405 g, p < 0.001).

CONCLUSION

Late-onset SGA syndromes are characterized by lower sFlt-1/PlGF ratios, which indicates a lower degree of placental function impairment. The sFlt-1/PlGF ratio can be a predictor of more significant growth disorders and a lower neonatal birth weight. The sFlt-1/PlGF ratio can be helpful in distinguishing between disordered angiogenesis-dependent and other causes of late-onset SGA cases.

Predicting intrapartum fetal compromise at term using the cerebroplacental ratio and placental growth factor levels (PROMISE) study: randomised controlled trial protocol

INTRODUCTION

Intrapartum complications are a major contributor to adverse perinatal outcomes, including stillbirth, hypoxic-ischaemic brain injury and subsequent longer term disability. In many cases, hypoxia develops as a gradual process due to the inability of the fetus to tolerate the stress of parturition suggesting reduced fetoplacental reserve before labour commences. The fetal cerebroplacental ratio (CPR) is an independent predictor of intrapartum fetal compromise, poor acid base status at birth and of neonatal unit admission at term. Similarly, circulating maternal levels of placental growth factor (PlGF) are lower in pregnancies complicated by placental dysfunction. This paper outlines the protocol for the PROMISE Study, which aims to determine if the introduction of a prelabour screening test for intrapartum fetal compromise combining the CPR and maternal PlGF level results in a reduction of adverse perinatal outcomes.

METHODS AND ANALYSIS

This is a single-site, non-blinded, individual patient randomised controlled trial of a screening test performed at term, combining the fetal CPR and maternal serum PlGF. Women with a singleton, non-anomalous pregnancy will be recruited after 34 weeks' gestation and randomised to either receive the screening test or not. Screened pregnancies determined to be at risk will be recommended induction of labour. Demographic, obstetric history and antenatal data will be collected at enrolment, and perinatal outcomes will be recorded after delivery. Relative risks and 95% CIs will be reported for the primary outcome. Regression techniques will be used to examine the influence of prognostic factors on the primary and secondary outcomes.

ETHICS AND DISSEMINATION

This study has been reviewed and approved by the Mater Human Research Ethics Committee (Reference: HREC EC00332) and will follow the principles of Good Clinical Practice. The study results will be disseminated at national and international conferences and published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ACTRN12616001009404; Pre-results.

Placental growth factor as an indicator of fetal growth restriction in late-onset small-for-gestational age pregnancies

BACKGROUND

At-risk small-for-gestational age (SGA) pregnancies in New Zealand are identified using Doppler ultrasound; fetuses with Doppler abnormalities are considered growth restricted (FGR). Low maternal placental growth factor (PlGF) has also been associated with late-onset FGR.

AIMS

To investigate whether low PlGF at diagnosis of late-onset SGA identifies the same fetuses classified FGR by detailed Doppler studies, and the association between low PlGF and adverse pregnancy outcomes.

METHODS

Among an historical database of normotensive suspected SGA pregnancies (fetal abdominal circumference <10th percentile) ≥32 weeks gestation, the ability of low PlGF (<5th percentile) to identify FGR infants was investigated. 'Initial FGR' was an abnormal umbilical artery resistance index (RI) or estimated fetal weight <3rd customised centile. 'Secondary FGR' was abnormal internal carotid RI, cerebro-placental ratio and/or mean uterine artery RI. Development of hypertensive disease and adverse perinatal outcomes were compared by PlGF status.

RESULTS

Of 136 SGA pregnancies, 56 (41.1%) had initial FGR. Of the remaining, 20 (25.0%) had secondary FGR, 17 (21.3%) low PlGF. The sensitivity of low PlGF identifying secondary FGR was 0.30 (95% CI 0.14-0.50), specificity 0.83 (0.70-0.92), positive predictive value 0.47 (0.23-0.72) and negative predictive value 0.70 (0.57-0.81). Overall, low PlGF occurred in 44/136 (32.4%) pregnancies and was associated with gestational hypertensive disease (63.6% vs 15.2%, P < 0.01), adverse perinatal outcome (34.1% vs 15.2%, P = 0.01) and very low birthweight (customised centile 2.2 vs 6.8, P < 0.01).

CONCLUSIONS

At diagnosis of late-onset SGA, low PlGF was poor at identifying Doppler-defined FGR. Low PlGF identified pregnancies at risk of hypertensive disease, adverse perinatal outcome and very low birthweight.

Systematic review of maternal Placental Growth Factor levels in late pregnancy as a predictor of adverse intrapartum and perinatal outcomes

AIM

This systematic review evaluates the utility of maternal Placental Growth Factor (PlGF) when measured in late pregnancy (>20 weeks) as a predictor of adverse obstetric and perinatal outcomes.

METHODS

Pubmed and Embase were searched using the term "placental growth factor" in combination with relevant perinatal outcomes. Studies were included if they measured PlGF levels in pregnant women after 20 + 0 weeks gestation and reported relevant adverse obstetric or perinatal outcomes related to placental insufficiency (excluding pre-eclampsia).

RESULTS

Twenty-six studies were eligible for inclusion with 21 studies investigating the relationship between PlGF and small for gestational age (SGA) and 7 studies investigating PlGF for the prediction of other adverse perinatal outcomes. In all studies, maternal PlGF levels were significantly lower in the SGA group compared to controls. Other outcomes investigated included caesarean section (CS) for fetal compromise, low Apgar score, neonatal intensive care unit (NICU) admission, neonatal acidosis, stillbirth, and intrapartum fetal compromise. The results generally showed a significant association between low PlGF levels and CS for fetal compromise, NICU admission and stillbirth.

CONCLUSION

Low maternal PlGF levels in late pregnancy are strongly associated with SGA. Findings across studies were variable in relation to PlGF and the prediction of other adverse intrapartum and perinatal outcomes, however there was a consistent association between low PlGF levels and CS for fetal compromise, NICU admission and stillbirth. This review suggests that the use of PlGF for the prediction of adverse outcomes is promising. Its predictive value may potentially be enhanced if used in combination with other biomarkers or biophysical measures of fetal well-being.

A Systematic Review of Placental Biomarkers Predicting Small-for-Gestational-Age Neonates

Background:

Neonates born small for gestational age (SGA) face increased risk of neonatal mortality, childhood developmental problems, and adult disease. The placenta is a key factor in SGA development because of its multiple biological processes that underlie fetal growth. However, valid and reliable placental biomarkers of SGA have not been determined.

Objectives:

The objective of this article was to systematically identify and review studies examining associations between placental biomarkers and SGA and assess those biomarkers’ predictive value.

Methods:

Use of the matrix method and the PRISMA guidelines ensured systematic identification of relevant articles based on selection criteria. PubMed, CINAHL, and EMBASE were searched for English articles published in 2005–2016 that addressed relationships between placental biomarkers and SGA.

Results:

The search captured 466 articles; 13 met selection criteria. The review identified 14 potential placental biomarkers for SGA, with placental growth factor and soluble fms-like tyrosine kinase 1 being the most commonly studied. However, findings for these and other biomarkers have often been contradictory. Thus, no placental biomarkers have been confirmed as reliable for predicting SGA.

Conclusion:

The inconsistent findings suggest low placental biomarker reliability, perhaps due to the multifactorial nature of SGA. This review is novel in its focus on identifying potential placental biomarkers for SGA, producing a better understanding of how placental function underlies fetal growth. Nevertheless, use of placental biomarkers alone may not be adequate for predicting SGA. Therefore, combinations of biomarkers and other predictive tests should be evaluated for their ability to predict risk of SGA.

Diagnosis and surveillance of late-onset fetal growth restriction

By consensus, late fetal growth restriction is that diagnosed >32 weeks. This condition is mildly associated with a higher risk of perinatal hypoxic events and suboptimal neurodevelopment. Histologically, it is characterized by the presence of uteroplacental vascular lesions (especially infarcts), although the incidence of such lesions is lower than in preterm fetal growth restriction. Screening procedures for fetal growth restriction need to identify small babies and then differentiate between those who are healthy and those who are pathologically small. First- or second-trimester screening strategies provide detection rates for late smallness for gestational age <50% for 10% of false positives. Compared to clinically indicated ultrasonography in the third trimester, universal screening triples the detection rate of late smallness for gestational age. As opposed to early third-trimester ultrasound, scanning late in pregnancy (around 37 weeks) increases the detection rate for birthweight <3rd centile. Contrary to early fetal growth restriction, umbilical artery Doppler velocimetry alone does not provide good differentiation between late smallness for gestational age and fetal growth restriction. A combination of biometric parameters (with severe smallness usually defined as estimated fetal weight or abdominal circumference <3rd centile) with Doppler criteria of placental insufficiency (either in the maternal [uterine Doppler] or fetal [cerebroplacental ratio] compartments) offers a classification tool that correlates with the risk for adverse perinatal outcome. There is no evidence that induction of late fetal growth restriction at term improves perinatal outcomes nor is it a cost-effective strategy, and it may increase neonatal admission when performed <38 weeks.

Prediction of fetal growth restriction using estimated fetal weight vs a combined screening model in the third trimester

OBJECTIVES

To compare the performance of third-trimester screening, based on estimated fetal weight centile (EFWc) vs a combined model including maternal baseline characteristics, fetoplacental ultrasound and maternal biochemical markers, for the prediction of small-for-gestational-age (SGA) neonates and late-onset fetal growth restriction (FGR).

METHODS

This was a nested case-control study within a prospective cohort of 1590 singleton gestations undergoing third-trimester (32 + 0 to 36 + 6 weeks' gestation) evaluation. Maternal baseline characteristics, mean arterial pressure, fetoplacental ultrasound and circulating biochemical markers (placental growth factor (PlGF), lipocalin-2, unconjugated estriol and inhibin A) were assessed in all women who subsequently delivered a SGA neonate (n = 175), defined as birth weight < 10^th centile according to customized standards, and in a control group (n = 875). Among SGA cases, those with birth weight < 3^rd centile and/or abnormal uterine artery pulsatility index (UtA-PI) and/or abnormal cerebroplacental ratio (CPR) were classified as FGR. Logistic regression predictive models were developed for SGA and FGR, and their performance was compared with that obtained using EFWc alone.

RESULTS

In SGA cases, EFWc, CPR Z-score and maternal serum concentrations of unconjugated estriol and PlGF were significantly lower, while mean UtA-PI Z-score and lipocalin-2 and inhibin A concentrations were significantly higher, compared with controls. Using EFWc alone, 52% (area under receiver-operating characteristics curve (AUC), 0.82 (95% CI, 0.77-0.85)) of SGA and 64% (AUC, 0.86 (95% CI, 0.81-0.91)) of FGR cases were predicted at a 10% false-positive rate. A combined screening model including a-priori risk (maternal characteristics), EFWc, UtA-PI, PlGF and estriol (with lipocalin-2 for SGA) achieved a detection rate of 61% (AUC, 0.86 (95% CI, 0.83-0.89)) for SGA cases and 77% (AUC, 0.92 (95% CI, 0.88-0.95)) for FGR. The combined model for the prediction of SGA and FGR performed significantly better than did using EFWc alone (P < 0.001 and P = 0.002, respectively).

CONCLUSIONS

A multivariable integrative model of maternal characteristics, fetoplacental ultrasound and maternal biochemical markers modestly improved the detection of SGA and FGR cases at 32-36 weeks' gestation when compared with screening based on EFWc alone. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Changes in uterine artery Doppler velocimetry and circulating angiogenic factors in the first half of pregnancies delivering a small-for-gestational-age neonate

OBJECTIVE

To assess the relationship between longitudinal changes in placental Doppler indices and maternal circulating angiogenic factors in the first half of pregnancy and delivery of a small-for-gestational-age (SGA) neonate, and ascertain whether longitudinal evaluation of these variables improves the prediction achieved by second-trimester cross-sectional evaluation.

METHODS

From a prospective cohort of unselected singleton pregnancies undergoing first-trimester screening for aneuploidy, 138 were included in this study. Of these, 46 were complicated by SGA (delivering after 34 weeks' gestation with a birth weight < 10^th centile) and 92 were appropriate-for-gestational-age (AGA) pregnancies, which were included as controls (ratio 1:2). First-to-second trimester longitudinal changes in uterine artery (UtA) Doppler indices and maternal circulating levels of placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1) were analyzed.

RESULTS

Compared with the AGA group, SGA pregnancies had significantly higher UtA impedance in the first (Z-score: 0.46 vs -0.57; P < 0.001) and second (Z-score: 1.71 vs -0.75; P < 0.001) trimesters. Likewise, the sFlt-1/PlGF ratio was significantly higher in SGA than in AGA pregnancies in the first (98.0 vs 67.9; P = 0.01) and early second (22.4 vs 8.8; P < 0.001) trimesters. The predictive performance of the longitudinal changes in UtA Doppler indices for SGA was significantly lower than that of second-trimester cross-sectional values (area under receiver-operating characteristics curve (AUC), 60.8% vs 84.3%; P = 0.0035). The detection rate of SGA, at a 10% false-positive rate (FPR), was 17.7% by longitudinal changes in UtA Doppler and 56.2% by second-trimester cross-sectional UtA Doppler values. Similarly, the predictive performance of the longitudinal changes in PlGF was significantly lower than that of early second-trimester cross-sectional values (AUC, 71.4% vs 76.5%; P = 0.008). The detection rate of SGA at a 10% FPR was 40.6% when screening by longitudinal changes in PlGF and 52.1% when screening by early second-trimester cross-sectional values.

CONCLUSIONS

First- and second-trimester UtA Doppler velocimetry and maternal circulating angiogenic markers have clinical utility as a cross-sectional assessment for the identification of pregnancies at high risk of delivering a SGA neonate, however, they do not improve prediction when their longitudinal changes are used. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Angiogenic proteins, placental weight and perinatal outcomes among pregnant women in Tanzania

Introduction

Placental vascular development, and ultimately placental weight, is essential to healthy fetal development. Here, we examined placental weight in a cohort of Tanzanian women in association with angiogenic proteins known to regulate placental vascular development and perinatal outcomes.

Methods

A total of n = 6579 women with recorded placental weight were included in this study. The relative risk of adverse perinatal outcomes (Apgar score, death, asphyxia, respiratory distress, seizures, pneumonia and sepsis) was compared between placental weight in the bottom and top 10^th percentiles. We quantified angiogenic mediators (Ang-1, Ang-2, VEGF, PGF and sFlt-1) in plasma samples (n = 901) collected between 12 to 27 weeks of pregnancy using ELISA and assessed the relative risk of placental weight in the bottom and top 10^th percentiles by protein levels in quartiles.

Results

Women with Ang-2 levels in the highest quartile had an increased relative risk of placental weight in the bottom 10^th percentile (RR = 1.45 (1.10, 1.91), p = 0.01). Women with VEGF-A (RR = 0.73 (0.56, 0.96), p = 0.05) and PGF (RR = 0.58 (0.44, 0.72), p = 0.002) in the highest quartile had a reduced relative risk of placental weight in the bottom 10^th percentile. Low placental weight (in bottom 10^th percentile) was associated with an increased relative risk of Apgar score of <7 at 1 minute (RR = 2.31 (1.70, 3.13), p = 0.001), at 5 minutes (RR = 3.53 (2.34, 5.33), p = 0.001), neonatal death (RR = 5.02 (3.61, 7.00), p = 0.001), respiratory distress (RR = 4.80(1.71, 13.45), p = 0.001), and seizures (RR = 4.18 (1.16, 15.02), p = 0.03).

Discussion

The association between low placental weight and risk of adverse perinatal outcomes in this cohort suggests that placental weight could serve as a useful indicator, providing additional insight into high-risk pregnancies and identifying neonates that may require additional monitoring and follow-up.

An integrated approach to fetal growth restriction

Fetal growth restriction (FGR) is among the most common complications of pregnancy. FGR is associated with placental insufficiency and poor perinatal outcomes. Clinical management is challenging because of variability in clinical presentation. Fetal smallness (estimated fetal weight <10th centile for gestational age) remains the best clinical surrogate for FGR. However, it is commonly accepted that not all forms of fetal smallness represent true FGR. In a significant subset of small fetuses, there is no evidence of placental involvement, perinatal outcomes are nearly normal, and they are clinically referred to as "only" small for gestational age (SGA). Doppler may improve the clinical management of FGR; however, the need to use several parameters sometimes results in a number of combinations that may render interpretation challenging when translating into clinical decisions. We propose that the management of FGR can be simplified using a sequential approach based on three steps: (1) identification of the "small fetus," (2) differentiation between FGR and SGA, and (3) timing of delivery according to a protocol based on stages of fetal deterioration.

The relationship between maternal placental growth factor levels and intrapartum fetal compromise

INTRODUCTION

Whilst some cases of intrapartum fetal compromise are the result of unpredictable catastrophic events, the majority arise from an unrecognised reduction in feto-placental reserve in otherwise healthy pregnancies. There is currently no reliable technique prior to labour that identifies the at-risk fetus. We aimed to investigate the relationship between maternal levels of serum placental growth factor (PlGF) and intrapartum fetal compromise in term pregnancies prior to labour. Secondary outcomes were caesarean delivery for intrapartum fetal compromise and adverse neonatal outcomes.

METHODS

A blinded, prospective, cross sectional study set at Mater Mother's Hospital, Brisbane, Australia. Maternal PlGF concentration was assessed fortnightly from 36 weeks until delivery in 378 low-risk pregnant women. Antenatal and intrapartum care was managed according to local protocols and guidelines, and intrapartum and neonatal outcomes were recorded.

RESULTS

Pregnancies that developed intrapartum fetal compromise had lower PlGF than those that did not. PlGF concentration was also lower amongst pregnancies that developed intrapartum fetal heart rate abnormalities, were delivered with abnormal cord gases or Apgar ≤7 at 5 min. Additionally, PlGF levels were lower in pregnancies with an adverse composite neonatal outcome.

DISCUSSION

Lower maternal PlGF concentration is associated with intrapartum fetal compromise and poorer condition of the newborn. Maternal PlGF levels may be useful as a component of a risk stratification tool for intrapartum fetal compromise in apparently 'low risk' term pregnancies prior to labour.

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

BACKGROUND

Placental lesions consistent with maternal vascular underperfusion (MVU) are thought to be pathogenically linked to preeclampsia, small-for-gestational-age newborns, fetal death, and spontaneous preterm labor and delivery; yet, these lesions cannot be diagnosed antenatally. We previously reported that patients with such conditions and lesions have an abnormal profile of the angiogenic placental growth factor (PlGF) and antiangiogenic factors (eg, soluble vascular endothelial growth factor receptor [sVEGFR]-1).

OBJECTIVE

The objectives of this study were to: (1) examine the relationship between the maternal plasma PlGF/sVEGFR-1 concentration ratio (referred to herein as angiogenic index-1) and the burden of histologic placental features consistent with MVU; and (2) test the hypothesis that angiogenic index-1 can identify patients in the midtrimester who are destined to deliver before 34 weeks of gestation with multiple (ie, ≥3) histologic placental features consistent with MVU.

STUDY DESIGN

A 2-stage case-cohort sampling strategy was used to select participants from among 4006 women with singleton gestations enrolled from 2006 through 2010 in a longitudinal study. Maternal plasma angiogenic index-1 ratios were determined using enzyme-linked immunosorbent assays. Placentas underwent histologic examination according to standardized protocols by experienced pediatric pathologists who were blinded to clinical diagnoses and pregnancy outcomes. The diagnosis of lesions consistent with MVU was made using criteria proposed by the Perinatal Section of the Society for Pediatric Pathology. Weighted analyses were performed to reflect the parent cohort; "n*" is used to reflect weighted frequencies.

RESULTS

(1) Angiogenic index-1 (PlGF/sVEGFR-1) concentration ratios were determined in 7560 plasma samples collected from 1499 study participants; (2) the prevalence of lesions consistent with MVU was 21% (n* = 833.9/3904) and 27% (n* = 11.4/42.7) of women with ≥3 MVU lesions delivered before 34 weeks of gestation; (3) a low angiogenic index-1 (<2.5th quantile for gestational age) in maternal plasma samples obtained within 48 hours of delivery had a sensitivity of 73% (n* = 8.3/11.4; 95% confidence interval [CI], 47-98%), a specificity of 94% (n* = 3130.9/3316.2; 95% CI, 94-95%), a positive likelihood ratio of 12.2, and a negative likelihood ratio of 0.29 in the identification of patients who delivered placentas with ≥3 MVU lesions at <34 weeks; (4) prospectively, at 20-23 weeks of gestation, a maternal plasma concentration of angiogenic index-1 <2.5th quantile identified 70% (n* = 7.2/10.3; 95% CI, 42-98%) of patients who delivered placentas with ≥3 MVU lesions before 34 weeks (specificity, 97% [n* = 2831.3/2918; 95% CI, 96-98%]; positive likelihood ratio, 23; negative likelihood ratio, 0.31); and (5) among women without obstetrical complications who delivered at term, angiogenic index-1 was lower in women with than without placental lesions consistent with MVU (P < .05).

CONCLUSION

Maternal plasma angiogenic index-1 (PlGF/sVEGFR-1) is the first biomarker for the burden of placental lesions consistent with MVU. We propose that an accumulation of these lesions in placentas delivered before 34 weeks is a histologic counterpart of an antiangiogenic profile.

Angiogenic Factors and Doppler Evaluation in Normally Growing Fetuses at Routine Third-Trimester Scan: Prediction of Subsequent Low Birth Weight

Objective: To evaluate in normally growing fetuses at routine 32-36 weeks scan the performance of maternal angiogenic factors, Doppler and ultrasound indices in predicting smallness for gestational age (SGA) at birth. Methods: A cohort of 1,000 singleton pregnancies with normal estimated fetal weight (EFW, ≥10th centile) at 32-36 weeks scan was included. At inclusion, Doppler indices (mean uterine artery pulsatility index [mUtA-PI], cerebroplacental ratio and normalized umbilical vein blood flow by EFW (ml/min/kg) were evaluated, and blood samples were collected and frozen. Nested in this cohort, maternal circulating placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1) were assayed by enzyme-linked immunosorbent assay in all cases with a birth weight <10th centile by customized standards and in an equivalent number of controls (birth weight ≥10th centile). Results: 160 cases were included (80 SGA and 80 controls). EFW (2,128 vs. 2,279 g, p < 0.001), mUtA-PI z-values (-0.25 vs. -0.65, p = 0.034) and sFlt-1/PlGF ratio (11.10 vs. 6.74, p < 0.005) were lower in SGA. The combination of sFlt-1/PlGF ratio and EFW resulted in a 66.3% detection rate for subsequent SGA, with 20% of false-positives. Fetal Doppler indices were not predictive of SGA. Conclusions: In normally growing fetuses, maternal angiogenic factors add to ultrasound parameters in predicting subsequent SGA at birth. This supports further research to investigate composite scores in order to improve the definition and identification of fetal growth restriction.

Placental 11B-Hydroxysteroid Dehydrogenase Type 2 mRNA Levels in Intrauterine Growth Restriction versus Small-for-Gestational-Age Fetuses

Introduction: The objective of this study was to evaluate placental 11B-hydroxysteroid dehydrogenase type 2 (11B-HSD-2) mRNA levels in intrauterine growth-restricted fetuses (IUGR) as compared with small-for-gestational-age (SGA) fetuses according to clinical criteria. Material and Methods: Placental levels of 11B-HSD-2 mRNA levels were measured in SGA (birth weight <10th centile) and gestational-age-matched, appropriate-for-gestational-age (AGA) births. SGA was classified as IUGR (birth weight <3rd centile or <10th percentile with abnormal uterine artery Doppler or cerebroplacental ratio) or non-IUGR SGA. After RNA extraction, mRNA levels were determined by reverse transcription and quantitative PCR. Results: A total of 38 placentas were analyzed (20 AGA and 18 SGA). Among the SGA pregnancies, 13 qualified as IUGR. The activity of 11B-HSD-2 in IUGR pregnancies [0.105 (SD 0.328)] was significantly reduced compared to non-IUGR SGA [0.304 (SD 0.261); p = 0.018] and AGA [0.294 (SD 0.328); p = 0.001]. These differences remained significant after adjusting for potential confounders (such as smoking or maternal cortisol levels). Activity levels did not significantly differ between non-IUGR SGA and AGA. Discussion: IUGR fetuses had reduced 11B-HSD-2 activity in comparison with SGA and normally grown fetuses. This finding provides opportunities to develop new placental biomarkers for the phenotypic characterization of fetal smallness.

Update on the pathophysiological implications and clinical role of angiogenic factors in pregnancy

Angiogenic markers are now being incorporated into clinical practice for the screening, diagnosing, and monitoring of preeclampsia. Pregnancy requires both vasculogenesis and angiogenesis in the fetal compartment and angiogenesis in the maternal compartment. Abnormal angiogenesis in the placenta determines impaired remodeling of the maternal spiral arteries and placental underperfusion that may ultimately lead to fetal growth restriction and maternal preeclampsia. The dysregulation of angiogenesis in the placenta and maternal-fetal circulation has emerged as one of the main pathophysiological features in the development of placental insufficiency and its clinical consequences. Abnormal angiogenesis has also been related to other obstetric and fetal conditions such as peripartum cardiomyopathy and fetal cardiac defects. This opens up new challenges for our understanding of angiogenic involvement in maternal cardiovascular function and fetal cardiac development, and it offers new clinical opportunities. This review summarizes the current knowledge of the pathophysiological implications and the clinical role of angiogenic factors in pregnancy.

Preeclampsia, placental insufficiency, and autism spectrum disorder or developmental delay

IMPORTANCE

Increasing evidence suggests that autism spectrum disorder (ASD) and many forms of developmental delay (DD) originate during fetal development. Preeclampsia may trigger aberrant neurodevelopment through placental, maternal, and fetal physiologic mechanisms.

OBJECTIVE

To determine whether preeclampsia is associated with ASD and/or DD.

DESIGN, SETTING, AND PARTICIPANTS

The Childhood Autism Risks from Genetics and the Environment (CHARGE) study is a population-based, case-control investigation of ASD and/or DD origins. Children from 20 California counties aged 24 to 60 months at the time of recruitment and living in catchment areas with a biological parent fluent in English or Spanish were enrolled from January 29, 2003, through April 7, 2011. Children with ASD (n = 517) and DD (n = 194) were recruited through the California Department of Developmental Services, the Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, and referrals. Controls with typical development (TD) (n = 350) were randomly selected from birth records and frequency matched on age, sex, and broad geographic region. Physicians diagnosing preeclampsia were masked to neurodevelopmental outcome, and those assessing neurodevelopmental function were masked to preeclampsia status.

EXPOSURES

Preeclampsia and placental insufficiency were self-reported and abstracted from medical records.

MAIN OUTCOMES AND MEASURES

The Autism Diagnostic Observation Schedule and Autism Diagnostic Interview-Revised were used to confirm ASD, whereas children with DD and TD were confirmed by Mullen Scales of Early Learning and Vineland Adaptive Behavior Scales and were free of autistic symptoms. Hypotheses were formulated before data collection.

RESULTS

Children with ASD were twice as likely to have been exposed in utero to preeclampsia as controls with TD after adjustment for maternal educational level, parity, and prepregnancy obesity (adjusted odds ratio, 2.36; 95% CI, 1.18-4.68); risk increased with greater preeclampsia severity (test for trend, P = .02). Placental insufficiency appeared responsible for the increase in DD risk associated with severe preeclampsia (adjusted odds ratio, 5.49; 95% CI, 2.06-14.64).

CONCLUSIONS AND RELEVANCE

Preeclampsia, particularly severe disease, is associated with ASD and DD. Faulty placentation manifests in the mother as preeclampsia with vascular damage, enhanced systemic inflammation, and insulin resistance; in the placenta as oxygen and nutrient transfer restriction and oxidative stress; and in the fetus as growth restriction and progressive hypoxemia. All are potential mechanisms for neurodevelopmental compromise.