Biophysical and biochemical markers at 30-34 weeks' gestation in the prediction of adverse perinatal outcome

Maternal Plasma Proteins Associated with Birth Weight: A Longitudinal, Large Scale Proteomic Study

Small infants for gestational age (SGA) and large infants for gestational age (LGA) have increased risk of complications during delivery and later in life. Prediction of the fetal weight is currently limited to biometric parameters obtained by ultrasound scans that can be imprecise. Biomarkers of fetal growth would be crucial for tailoring clinical management and optimizing outcomes for the mother and child. Seventy pregnant women participated in the current study, including 58, 7, and 5 giving birth to adequate for gestational age (AGA), SGA, and LGA infants, respectively. Maternal venous blood was drawn at gestational weeks 12-19, 21-27, and 28-34 and quantified for nearly 5000 proteins on the SomaLogic platform. We used machine learning algorithms with leave-one-out cross-validation to construct multiprotein models for prediction of birth weight groups. Random forest models using only 20 predefined proteins (selected by moderated t tests) were able to predict LGA with good discrimination (AUC > 0.8) at all three visits, while prediction of SGA was less successful. Protein differential abundance analysis revealed 148 proteins with higher abundance in LGA compared to AGA pregnancies, while only four proteins were differentially abundant between the SGA and AGA. The principal findings indicate that the maternal plasma proteome may hold potential biomarkers of LGA.

Prediction models for intrapartum fetal hypoxia: A systematic review

BACKGROUND

Intrapartum fetal hypoxia (IFH) occurs infrequently and many cases occur unexpectedly, highlighting the importance of identifying at-risk fetuses to prevent hypoxic injury during birth.

OBJECTIVES

This systematic review aims to evaluate existing prediction models for IFH and ascertain the predictor variables that were incorporated into most models.

SEARCH STRATEGY

We searched MEDLINE and EMBASE databases from inception to December 2023 for synonyms of fetal distress, operative birth and neonatal asphyxia, with a filter for prediction models.

SELECTION CRITERIA

Prediction models for IFH were included. IFH was defined as evidence of hypoxia or operative intervention for suspected fetal distress.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted information on study design, outcome definition and validation. We evaluated study quality using the PROBAST tool. The number of models in which each predictor variable significantly contributed to the risk of IFH was quantified.

MAIN RESULTS

From 874 articles, 23 publications reported on 41 eligible prediction models. 32 models reported on model development only, while seven models across three studies included both development and internal validation. Of these, two models were also externally validated and refit to the validation data, but investigated fetuses with antenatally-suspected growth restriction, limiting generalisability. Frequently reported predictor variables included parity (13 studies), cerebroplacental ratio (10 studies) and oxytocin use (6 studies).

CONCLUSIONS

No prediction models for IFH applicable to the general population are currently ready for clinical application. External validation of existing models or development of new, reliable models applicable to all pregnant women is needed.

Widely accessible prognostication using medical history for fetal growth restriction and small for gestational age in nationwide insured women

Prevention of fetal growth restriction/small for gestational age (FGR/SGA) is adequate if screening is accurate. Ultrasound and biomarkers can achieve this goal; however, both are often inaccessible. This study aimed to develop, validate, and deploy a prognostic prediction model for screening FGR/SGA using only medical history. From a nationwide health insurance database (n = 1,697,452), we retrospectively selected visits to 22,024 healthcare providers of primary, secondary, and tertiary care. This study used machine learning (including deep learning) to develop prediction models using 54 medical-history predictors. After evaluating model calibration, clinical utility, and explainability, we selected the best by discrimination ability. We also externally validated the models using geographical and temporal splits of ~ 20% of the selected visits. The models were also compared with those from previous studies, which were rigorously selected by a systematic review of Pubmed, Scopus, and Web of Science. We selected 169,746 subjects with 507,319 visits for predictive modeling from the database, which were 12-to-55-year-old female insurance holders who used the healthcare services. The best prediction model was a deep-insight visible neural network. It had an area under the receiver operating characteristics curve of 0.742 (95% confidence interval 0.734 to 0.750) and a sensitivity of 49.09% (95% confidence interval 47.60-50.58% using a threshold with 95% specificity). The model was competitive against the previous models of 30 eligible studies of 381 records, including those using either ultrasound or biomarker measurements. We deployed a web application to apply the model. Our model used only medical history to improve accessibility for FGR/SGA screening. However, future studies are warranted to evaluate if this model's usage impacts patient outcomes.

Angiogenic factors alone or in combination with ultrasound Doppler criteria for risk classification among late-onset small fetuses with or without pre-eclampsia

OBJECTIVE

To investigate the prognostic value of maternal angiogenic factors in late-onset small fetuses, alone or in combination with the ultrasound and Doppler parameters currently used for the classification of low-risk small-for-gestational-age (SGA) fetuses or high-risk fetal growth restriction (FGR), overall and according to the presence or absence of pre-eclampsia.

METHODS

This was a prospective cohort study of women with a singleton pregnancy with a diagnosis of late-onset fetal smallness (defined as birth weight < 10th centile) and a gestational age of ≥ 34 weeks at delivery. Ultrasound assessment of estimated fetal weight (EFW) and Doppler assessment of uterine artery pulsatility index (UtA-PI) and cerebroplacental ratio (CPR) were performed every 1-2 weeks. Biochemical analysis of the angiogenic factors placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1) in maternal peripheral venous blood samples was performed using enzyme-linked immunosorbent assay within 1-2 weeks after diagnosis of SGA or FGR. The primary outcome was adverse perinatal outcome, defined as a composite of emergency Cesarean section for non-reassuring fetal status, metabolic acidosis (umbilical artery pH < 7.0), neonatal unit admission and/or perinatal death. The predictive value of EFW < 3rd centile, Doppler parameters (UtA-PI > 95th centile and CPR < 5th centile) and sFlt-1/PlGF ratio > 95th centile, alone or in combination, was assessed using logistic regression analysis in the overall population and stratified by presence or absence of pre-eclampsia developing at any time before delivery.

RESULTS

Among the 602 included cases, 91 (15.1%) developed pre-eclampsia and 511 (84.9%) did not. In the overall study population, all parameters were associated independently with adverse perinatal outcome: EFW < 3rd centile (adjusted odds ratio (aOR), 2.58 (95% CI, 1.67-4.00)), UtA-PI > 95th centile (aOR, 1.92 (95% CI, 1.25-2.94)), CPR < 5th centile (aOR, 2.35 (95% CI, 1.46-3.78)) and sFlt-1/PlGF ratio > 95th centile (aOR, 1.71 (95% CI, 1.09-2.69)). Only sFlt-1/PlGF ratio > 95th centile was associated independently with adverse perinatal outcome in cases with pre-eclampsia, whereas in those without pre-eclampsia, only EFW < 3rd centile and CPR < 5th centile were associated independently with adverse perinatal outcome. In the overall population, the detection rate (DR) and false-positive rate for adverse perinatal outcome were, respectively: 39.8% (95% CI, 31.7-47.9%) and 16.9% (95% CI, 10.7-23.1%) for sFlt-1/PlGF ratio > 95th centile alone; 86.8% (95% CI, 83.4-90.2%) and 61.9% (95% CI, 57.1-66.7%) for a combined model of EFW < 3rd centile, UtA-PI > 95th centile and CPR < 5th centile; 81.3% (95% CI, 77.3-85.3%) and 52.3% (95% CI, 47.1-57.5%) for a combined model of EFW < 3rd centile and sFlt-1/PlGF ratio > 95th centile; and 88.5% (95% CI, 85.4-91.6%) and 64.5% (95% CI, 59.8-69.2%) for a combined model including all the abovementioned observed parameters.

CONCLUSIONS

sFlt-1/PlGF ratio alone had a low predictive value for adverse perinatal outcome, but when combined with EFW, its predictive performance was similar to that of EFW combined with Doppler parameters. Combining sFlt-1/PlGF ratio with EFW and Doppler criteria achieved the highest DR for adverse perinatal outcome, and additionally, might help to identify imminent pre-eclampsia in pregnancies complicated by fetal smallness. These findings support the use of angiogenic factors as an additional criterion to those currently used for identifying high-risk FGR among late-onset small fetuses, but do not support their use as a standalone biomarker. © 2025 International Society of Ultrasound in Obstetrics and Gynecology.

The ratio of soluble fms-like tyrosine kinase 1 to placental growth factor predicts time to delivery and mode of birth in patients with suspected preeclampsia: a secondary analysis of the INSPIRE trial

BACKGROUND

The ratio of soluble fms-like tyrosine kinase 1 to placental growth factor is a useful biomarker for preeclampsia. Since it is a measure of placental dysfunction, it could also be a predictor of clinical deterioration and fetal tolerance to intrapartum stress.

OBJECTIVE

We tested the hypothesis that soluble fms-like tyrosine kinase 1 to placental growth factor ratio predicts time to delivery. Secondary objectives were to examine associations between the soluble fms-like tyrosine kinase 1 to placental growth factor ratio and mode of birth, fetal distress, need for labor induction, and birthweight z score.

STUDY DESIGN

Secondary analysis of the INSPIRE trial, a randomized interventional study on prediction of preeclampsia/eclampsia in which women with suspected preeclampsia were recruited and their blood soluble fms-like tyrosine kinase 1 to placental growth factor ratio was assessed. We stratified participants into 3 groups according to the ratio result: category 1 (soluble fms-like tyrosine kinase 1 to placental growth factor ≤38); category 2 (soluble fms-like tyrosine kinase 1 to placental growth factor >38 and <85); and category 3 (soluble fms-like tyrosine kinase 1 to placental growth factor ≥85). We modeled time from soluble fms-like tyrosine kinase 1 to placental growth factor determination to delivery using Kaplan-Meier curves and compared the 3 ratio categories adjusting for gestational age at soluble fms-like tyrosine kinase 1 to placental growth factor determination and trial arm with Cox regression. The association between ratio category and mode of delivery, induction of labor, and fetal distress was assessed using a multivariable logistic regression adjusting for gestational age at sampling and trial arm. The association between birthweight z score and soluble fms-like tyrosine kinase 1 to placental growth factor ratio was evaluated using multiple linear regression. Subgroup analysis was conducted in women with no preeclampsia and spontaneous onset of labor; women with preeclampsia; and participants in the nonreveal arm.

RESULTS

Higher ratio categories were associated with a shorter latency from soluble fms-like tyrosine kinase 1 to placental growth factor determination to delivery (37 vs 13 vs 10 days for ratios categories 1-3 respectively), hazards ratio for category 3 ratio of 5.64 (95% confidence interval 4.06-7.84, P<.001). A soluble fms-like tyrosine kinase 1 to placental growth factor ratio ≥85 had specificity of 92.7% (95% confidence interval 89.0%-95.1%) and sensitivity of 54.72% (95% confidence interval, 41.3-69.5) for prediction of preeclampsia indicated delivery within 2 weeks. A ratio category 3 was also associated with decreased odds of spontaneous vaginal delivery (Odds ratio [OR] 0.47, 95% confidence interval 0.25-0.89); an almost 6-fold increased risk of emergency cesarean section (OR 5.89, 95% confidence interval 3.05-11.21); and a 2-fold increased risk for intrapartum fetal distress requiring operative delivery or cesarean section (OR 3.04, 95% confidence interval 1.53-6.05) when compared to patients with ratios ≤38. Higher ratio categories were also associated with higher odds of induction of labor when compared to ratios category 1 (category 2, OR 2.20, 95% confidence interval 1.02-4.76; category 3, OR 6.0, 95% confidence interval 2.01-17.93); and lower median birthweight z score. Within subgroups of women a) without preeclampsia and with spontaneous onset of labor and b) women with preeclampsia, the log ratio was significantly higher in patients requiring intervention for fetal distress or failure to progress compared to those who delivered vaginaly without intervention. In the subset of women with no preeclampsia and spontaneous onset of labor, those who required intervention for fetal distress or failure to progress had a significantly higher log ratio than those who delivered vaginaly without needing intervention.

CONCLUSION

The soluble fms-like tyrosine kinase 1 to placental growth factor ratio might be helpful in risk stratification of patients who present with suspected preeclampsia regarding clinical deterioration, intrapartum fetal distress, and mode of birth (including the need for intervention in labor).

Biomarkers in the prediction of complications in pregnancy after assisted reproductive technology

OBJECTIVES

To compare the temporal changes in mean arterial pressure (MAP), uterine artery pulsatility index (UtA-PI), placental growth factor (PlGF), and soluble fms-like tyrosine kinase-1 (sFlt-1) across gestation between assisted reproductive technology (ART) pregnancies complicated with great obstetrical syndromes (GOS) or gestational diabetes (GDM) ± large-for-gestational-age (LGA) fetus, and uncomplicated ART pregnancies.

METHODS

This was a prospective longitudinal study of 143 women with singleton pregnancies who conceived through ART at the Department of Obstetrics and Gynecology, Prince of Wales Hospital, the Chinese University of Hong Kong, Hong Kong SAR between December 2017 and January 2020. The participants were followed up at 6-6+3, 11-13+6, 20-24+6, 30-34+6, and 35-37+6 weeks for the measurement of MAP, UtA-PI, PlGF, and sFlt-1. A linear mixed-effects analysis was performed to compare the biomarkers in the GOS, GDM ± LGA, and uncomplicated groups across gestation.

RESULTS

Thirty-three (23.1%) and fifty-five (31.5%) women were diagnosed with GOS and GDM ± LGA, respectively. The GOS group had higher estimated marginal mean log10 MAP mulitples of the median (MoM) across gestation, compared with the uncomplicated group (0.00771 vs -0.02022; P < 0.001), when adjusting for clinical visits and days of embryo transfer. The absolute mean log10 MAP MoM in the GOS group was found to be significantly higher than that of the uncomplicated group at all clinical visits from 6 weeks onwards. Furthermore, the estimated marginal mean log10 PlGF MoM was significantly lower in the GOS group across gestation, compared with the uncomplicated group (-0.04226 vs 0.05566; P = 0.010). The significant difference in log10 PlGF MoM was observed from 11-13+6 to 30-34+6 week of gestation (P < 0.05). However, no significant differences in the estimated marginal means of log10 UtA-PI MoM and log10 sFlt-1 MoM between GOS and uncomplicated groups were observed. GDM ± LGA group had a lower estimated marginal mean log10 PlGF MoM throughout pregnancy compared with the uncomplicated group (-0.01536 vs 0.05572; P = 0.032). In the individual visit analysis, the significant difference was observed at the 20-24+6 and 35-37+6 weeks visits (P < 0.05). There were no significant differences in estimated marginal mean log10 MoM of MAP, UtA-PI, and sFlt-1 between GDM ± LGA and uncomplicated groups during pregnancy.

CONCLUSION

Our study has revealed that among pregnancies conceived through ART, GOS is associated with higher MAP and lower PlGF from early gestation until late third trimester, while GDM ± LGA is associated with lower PlGF during the second half of pregnancy. The same degree of differences in MAP and PlGF persists from early until late gestation in the GOS group and these findings highlight the importance of early screening during the first trimester to identify women who are at risk for developing GOS following ART procedures. Lastly, the potential of PlGF in predicting the development of GDM from the second trimester of pregnancy requires further investigation.

Added Value in Low-Risk Pregnancies of Longitudinal Changes in Uterine Doppler and Circulating Angiogenic Factors during the Third Trimester in Predicting Term Preeclampsia

INTRODUCTION

The objective of this study was to assess the relationship between longitudinal changes in the uterine Doppler velocimetry and the maternal profile of angiogenic factors in the third trimester and to assess their ability to predict term preeclampsia (PE).

METHODS

A cohort of low-risk pregnant women was scheduled for a uterine Doppler evaluation and measurement of the circulating levels of angiogenic factors at ∼30 and ∼36 weeks. The performance of both parameters and their change over time in predicting term PE was evaluated.

RESULTS

A total of 1,191 women were analyzed, of which 28 (2.4%) women developed term PE. At ∼30 weeks, a model including the sFlt-1/PlGF (fms-like tyrosine kinase-1/placental growth factor) ratio and the uterine Doppler explained 16.2% of the uncertainty of developing term PE, while at ∼36 weeks, the same variables explained 25.2% [p < 0.001]. The longitudinal changes of both predictors had an R2 of 26.8%, which was not different from that of the ∼36 weeks evaluation [p = 0.45]. The area under the curve (AUC) of the ∼36 weeks ratio was significantly higher than at ∼30 weeks (0.86 [0.77-0.94] vs. 0.81 [0.73-0.9]; p = 0.043). The AUC of the longitudinal change of the ratio (0.85 [0.77-0.94]) did not differ from that of at ∼36 weeks (p = 0.82). At ∼36 weeks, for a 10% of false positives, the ratio had a detection rate of 71.4%.

CONCLUSION

A cross-sectional measurement of the sFlt-1/PlGF ratio outperforms uterine Doppler in predicting term PE. The combination of both markers does not improve such prediction, nor the evaluation of the longitudinal changes between weeks.

The Right Ventricular Fetal Tricuspid Annular Plane Systolic Excursion Index Is a New Index for Evaluating Fetal Cardiac Function of Gestational Hypertension

ABSTRACT

The right ventricular fetal tricuspid annular plane systolic excursion index (FTI) can be used to evaluate right ventricular systolic function. The purpose of this study was to establish the reference range of the FTI in normal fetuses and evaluate its diagnostic value in hypertensive disorders during pregnancy. In this prospective observational study, the right ventricular FTI was measured in 208 normal single-gestation fetuses between 20 and 40 weeks. With the increase in gestational age, the right ventricular FTI did not significantly fluctuate. With the increase in the severity of HDCP, the right ventricular FTI decreased gradually. Compared with the normal group, the low right ventricular FTI group had a higher incidence of premature delivery and emergency delivery due to continuous abnormal fetal heart monitoring, but there were no significant differences in low birth weight, new born Apgar score less than 7 in 5 minutes, or admission to the neonatal intensive care unit. The FTI of the right ventricle of normal fetuses is relatively constant at different gestational weeks. The right ventricular FTI can be used to evaluate fetal cardiac function changes in pregnant women with HDCP.

Placental growth factor and fetoplacental Doppler indices in combination predict preterm birth reliably in pregnancies complicated by fetal growth restriction

OBJECTIVE

To assess the association between placental biomarkers (placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1)/PlGF ratio) and fetoplacental Doppler indices (umbilical artery (UA) pulsatility index (PI) and uterine artery (UtA) PI) in various combinations for predicting preterm birth (PTB) in pregnancies complicated by fetal growth restriction (FGR).

METHODS

This was a prospective observational cohort study, performed at Mater Mother's Hospital in Brisbane, Queensland, Australia, from May 2022 to June 2023, of pregnancies complicated by FGR and appropriate-for-gestational-age (AGA) pregnancies. Maternal serum PlGF levels, sFlt-1/PlGF ratio, UA-PI and UtA-PI were measured at 2-4-weekly intervals from recruitment until delivery. Harrell's concordance statistic (Harrell's C) was used to evaluate multivariable Cox proportional hazards regression models featuring various combinations of placental biomarkers and fetoplacental Doppler indices to ascertain the best combination to predict PTB (< 37 weeks). Multivariable Cox regression models were used with biomarkers as time-varying covariates.

RESULTS

The study cohort included 320 singleton pregnancies, comprising 179 (55.9%) affected by FGR, defined according to a Delphi consensus, and 141 (44.1%) with an AGA fetus. In the FGR cohort, both low PlGF levels and elevated sFlt-1/PlGF ratio were associated with significantly shorter time to PTB. Low PlGF was a better predictor of PTB than was either sFlt-1/PlGF ratio or a combination of PlGF and sFlt-1/PlGF ratio (Harrell's C, 0.81, 0.78 and 0.79, respectively). Although both Doppler indices were significantly associated with time to PTB, in combination they were better predictors of PTB than was either UA-PI > 95th centile or UtA-PI > 95th centile alone (Harrell's C, 0.82, 0.75 and 0.76, respectively). Predictive utility for PTB was best when PlGF < 100 ng/L, UA-PI > 95th centile and UtA-PI > 95th centile were combined (Harrell's C, 0.88) (hazard ratio, 32.99; 95% CI, 10.74-101.32).

CONCLUSIONS

Low maternal serum PlGF level (< 100 ng/L) and abnormal fetoplacental Doppler indices (UA-PI > 95th centile and UtA-PI > 95th centile) in combination have the greatest predictive utility for PTB in pregnancies complicated by FGR. Their assessment may help guide clinical management of these complex pregnancies. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Ophthalmic artery Doppler and biomarkers of impaired placentation at 36 weeks' gestation in pregnancies with small fetuses

OBJECTIVES

First, to compare ophthalmic artery peak systolic velocity (PSV) ratio and biomarkers of impaired placentation at 36 weeks' gestation in women who delivered a small-for-gestational-age (SGA) or growth-restricted (FGR) neonate, in the absence of hypertensive disorder, with those of women who developed pre-eclampsia (PE) or gestational hypertension (GH) and of women unaffected by SGA, FGR, PE or GH. Second, to examine the associations of PSV ratio, uterine artery pulsatility index (UtA-PI), placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1) with birth-weight Z-score or percentile.

METHODS

This was a prospective observational study of women with a singleton pregnancy attending for a routine hospital visit at 35 + 0 to 36 + 6 weeks' gestation. This visit included recording of maternal demographic characteristics and medical history, ultrasound examination of fetal anatomy and growth, and measurement of maternal ophthalmic artery PSV ratio, UtA-PI, PlGF and sFlt-1. Values of PSV ratio, UtA-PI, PlGF and sFlt-1 were converted to multiples of the median (MoM) or delta values. Median MoM or deltas of these biomarkers in the SGA, FGR, PE and GH groups were compared with those in the unaffected group. Regression analysis was used to examine the relationship of PSV ratio delta, UtA-PI MoM, PlGF MoM and sFlt-1 MoM with birth-weight Z-score, after exclusion of PE and GH cases.

RESULTS

The study population of 9033 pregnancies included 7696 (85.2%) that were not affected by FGR, SGA, PE or GH, 182 (2.0%) complicated by FGR in the absence of PE or GH, 698 (7.7%) with SGA in the absence of FGR, PE or GH, 236 (2.6%) with PE and 221 (2.4%) with GH. Compared with unaffected pregnancies, in the FGR and SGA groups, the PSV ratio delta and sFlt-1 MoM were increased and PlGF MoM was decreased; UtA-PI MoM was increased in the FGR group but not the SGA group. The magnitude of the changes in biomarker values relative to the unaffected group was smaller in the FGR and SGA groups than that in the PE and GH groups. In non-hypertensive pregnancies, there were significant inverse associations of PSV ratio delta and UtA-PI MoM with birth-weight Z-score, such that the values were increased in small babies and decreased in large babies. There was a quadratic relationship between PlGF MoM and birth-weight Z-score, with low PlGF levels in small babies and high PlGF levels in large babies. There was no significant association between sFlt-1 MoM and birth-weight Z-score.

CONCLUSIONS

Ophthalmic artery PSV ratio, reflective of peripheral vascular resistance, and UtA-PI, PlGF and sFlt-1, biomarkers of impaired placentation, are altered in pregnancies complicated by hypertensive disorder and, to a lesser extent, in non-hypertensive pregnancies delivering a SGA or FGR neonate. The associations between the biomarkers and birth-weight Z-score suggest the presence of a continuous physiological relationship between fetal size and peripheral vascular resistance and placentation, rather than a dichotomous relationship of high peripheral resistance and impaired placentation in small compared to non-small fetuses. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Safety and dose-finding trial of tadalafil administered for fetus in labor: A phase I clinical study

AIM

This study aimed to investigate the safety and efficacy of tadalafil in protecting the fetus from hypoxic stress caused by repeated labor pains during delivery and preventing fetal hypoxic-ischemic encephalopathy.

METHODS

The study used a three-case cohort approach. Three patients were administered 10 mg tadalafil and monitored for serious adverse events. In the absence of serious tadalafil-associated adverse events as assessed by the Safety Evaluation Committee, three new patients were added to the study and treated with 20 mg/dose. The blood levels of tadalafil were recorded before and after 2, 4, 8, and 12 h of administration and 2 h after delivery.

RESULTS

A total of seven patients were enrolled, and after excluding one patient who delivered before 37 weeks, tadalafil was administered to six patients. Maternal adverse events were considered acceptable from the maternal perspective, with grade 1 headache, anorexia, and myalgia and no obstetrical complications after delivery at both doses. No serious neonatal adverse events were associated with tadalafil. Tadalafil blood levels remained stable at both doses. In addition, the level of soluble fms-like tyrosine kinase-1 did not alter, while that of the placental growth factor differed significantly before and after tadalafil administration.

CONCLUSIONS

The study confirmed the safety of tadalafil administration during delivery for both mothers and newborns. The stable tadalafil blood levels confirmed the efficacy of the tested administration regime at 12 h interval. These findings would assist in conducting phase II trials to further verify the optimal dose and safety of tadalafil.

Diagnostic performance of 32 vs 36 weeks ultrasound in predicting late-onset fetal growth restriction and small-for-gestational-age neonates: a systematic review and meta-analysis

OBJECTIVE

Fetal growth restriction is an independent risk factor for fetal death and adverse neonatal outcomes. The main aim of this study was to investigate the diagnostic performance of 32 vs 36 weeks ultrasound of fetal biometry in detecting late-onset fetal growth restriction and predicting small-for-gestational-age neonates.

DATA SOURCES

A systematic search was performed to identify relevant studies published until June 2022, using the databases PubMed, Web of Science, and Scopus.

STUDY ELIGIBILITY CRITERIA

Cohort studies in low-risk or unselected singleton pregnancies with screening ultrasound performed at ≥32 weeks of gestation were used.

METHODS

The estimated fetal weight and abdominal circumference were assessed as index tests for the prediction of small for gestational age (birthweight of <10th percentile) and detecting fetal growth restriction (estimated fetal weight of <10th percentile and/or abdominal circumference of <10th percentile). The quality of the included studies was independently assessed by 2 reviewers using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. For the meta-analysis, hierarchical summary area under the receiver operating characteristic curves were constructed, and quantitative data synthesis was performed using random-effects models.

RESULTS

The analysis included 25 studies encompassing 73,981 low-risk pregnancies undergoing third-trimester ultrasound assessment for growth, of which 5380 neonates (7.3%) were small for gestational age at birth. The pooled sensitivities for estimated fetal weight of <10th percentile and abdominal circumference of <10th percentile in predicting small for gestational age were 36% (95% confidence interval, 27%-46%) and 37% (95% confidence interval, 19%-60%), respectively, at 32 weeks ultrasound and 48% (95% confidence interval, 41%-56%) and 50% (95% confidence interval, 25%-74%), respectively, at 36 weeks ultrasound. The pooled specificities for estimated fetal weight of <10th percentile and abdominal circumference of <10th percentile in detecting small for gestational age were 93% (95% confidence interval, 91%-95%) and 95% (95% confidence interval, 85%-98%), respectively, at 32 weeks ultrasound and 93% (95% confidence interval, 91%-95%) and 97% (95% confidence interval, 85%-98%), respectively, at 36 weeks ultrasound. The observed diagnostic odds ratios for an estimated fetal weight of <10th percentile and an abdominal circumference of <10th percentile in detecting small for gestational age were 8.8 (95% confidence interval, 5.4-14.4) and 11.6 (95% confidence interval, 6.2-21.6), respectively, at 32 weeks ultrasound and 13.3 (95% confidence interval, 10.4-16.9) and 36.0 (95% confidence interval, 4.9-260.0), respectively, at 36 weeks ultrasound. The pooled sensitivity, specificity, and diagnostic odds ratio in predicting fetal growth restriction were 71% (95% confidence interval, 52%-85%), 90% (95% confidence interval, 79%-95%), and 25.8 (95% confidence interval, 14.5-45.8), respectively, at 32 weeks ultrasound and 48% (95% confidence interval, 41%-55%), 94% (95% confidence interval, 93%-96%), and 16.9 (95% confidence interval, 10.8-26.6), respectively, at 36 weeks ultrasound. Abdominal circumference of <10th percentile seemed to have comparable sensitivity to estimated fetal weight of <10th percentile in predicting small-for-gestational-age neonates.

CONCLUSION

An ultrasound assessment of the fetal biometry at 36 weeks of gestation seemed to have better predictive accuracy for small-for-gestational-age neonates than an ultrasound assessment at 32 weeks of gestation. However, an opposite trend was noted when the outcome was fetal growth restriction. Fetal abdominal circumference had a similar predictive accuracy to that of estimated fetal weight in detecting small-for-gestational-age neonates.

Abnormal umbilical artery pulsatility index in appropriately grown fetuses in the early third trimester: an observational cohort study

OBJECTIVE

The aim of this study was to determine if appropriately grown fetuses (those that are not small-for-gestational-age) with a raised umbilical artery pulsatility index (>95th centile) in the mid third trimester are at increased risk of placental dysfunction and adverse outcome.

METHODS

This is a 5-year retrospective cohort study using routinely collected data. Inclusion criteria were singleton, non-anomalous pregnancies having a growth scan with umbilical artery Doppler velocimetry between 28 + 0 and 33 + 6 weeks' gestation. Small-for-gestational-age fetuses were excluded. Cases were classified as group 1 (those with an umbilical artery pulsatility index >95th centile at any scan during target window) or group 2 (those where the umbilical artery pulsatility index was ≤95th centile at all scans). p-Values and odds ratios were calculated. Logistic regression was used to compute odds ratios adjusted for baseline estimated weight z-score, gestational age at delivery, and labor induction.

RESULTS

After exclusions, there were 202 pregnancies in group 1 and 7950 in group 2. Differences in baseline characteristics between the groups include age (median age was 30 for group 1 and 32 for group 2, p < .001), smoking (group 1 were more likely to smoke, p < .001) and labor induction (more common in group 1, p = .03). Among those delivering ≥34 + 0, group 1 were more likely to be small-for-gestational-age and have an abnormal cerebro-placental ratio at the final scan (OR 6.76, CI 4.23-10.80 and OR 5.07, CI 3.37-7.63 respectively), and to develop features of growth restriction (OR 9.85, CI 6.27-15.49). Group 1 were also more likely to deliver <37 + 0 weeks' gestation (OR 1.71, CI 1.13-2.58) and to have birthweight <10th or <3rd centile (OR 5.26, CI 3.65-7.58 and OR 6.13, CI 3.00-12.54 respectively). These associations remained significant when adjusted for estimated weight at the initial scan.

CONCLUSIONS

These data suggest that raised umbilical artery pulsatility index in an appropriately grown fetus at 28 + 0 to 33 + 6 weeks' gestation is associated with subsequent development of growth restriction markers and an increased risk of moderate and severe small-for-gestational-age at birth. This is independent of the estimated weight of these babies at the index scan.

Circulating biomarkers associated with placental dysfunction and their utility for predicting fetal growth restriction

Fetal growth restriction (FGR) leading to low birth weight (LBW) is a major cause of neonatal morbidity and mortality worldwide. Normal placental development involves a series of highly regulated processes involving a multitude of hormones, transcription factors, and cell lineages. Failure to achieve this leads to placental dysfunction and related placental diseases such as pre-clampsia and FGR. Early recognition of at-risk pregnancies is important because careful maternal and fetal surveillance can potentially prevent adverse maternal and perinatal outcomes by judicious pregnancy surveillance and careful timing of birth. Given the association between a variety of circulating maternal biomarkers, adverse pregnancy, and perinatal outcomes, screening tests based on these biomarkers, incorporating maternal characteristics, fetal biophysical or circulatory variables have been developed. However, their clinical utility has yet to be proven. Of the current biomarkers, placental growth factor and soluble fms-like tyrosine kinase 1 appear to have the most promise for placental dysfunction and predictive utility for FGR.

Predictive index for adverse perinatal outcome in pregnancies complicated by fetal growth restriction

OBJECTIVES

To develop and validate an index predictive of adverse perinatal outcome (APO) in pregnancies meeting the consensus-based criteria for fetal growth restriction (FGR) endorsed by the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG).

METHODS

This was a retrospective analysis of consecutive singleton non-anomalous gestations meeting the ISUOG-endorsed criteria for FGR at a single tertiary care center from November 2010 to August 2020. The dataset was divided randomly into a development set (two-thirds) and a validation set (one-third). The primary composite APO comprised one or more of: perinatal demise, Grade III-IV intraventricular hemorrhage (IVH), periventricular leukomalacia (PVL), seizures, hypoxic ischemic encephalopathy (HIE), necrotizing enterocolitis (NEC), sepsis, bronchopulmonary dysplasia (BPD) and length of stay in the neonatal intensive care unit (NICU) > 7 days. Regression analysis incorporated clinical factors readily available at the time of FGR diagnosis. The sum of β coefficient-based weights yielded an index score, the performance of which was assessed in the validation set. Score cut-offs were selected to identify 'high-risk' and 'low-risk' ranges for which positive (PPV) and negative (NPV) predictive values and positive (LR+) and negative (LR-) likelihood ratios were calculated.

RESULTS

Of the 875 consecutive pregnancies that met the criteria for FGR and were included in the study cohort, 405 (46%) were complicated by one or more components of the composite APO, including 54 (6%) perinatal deaths, 22 (3%) neonates with Grade III-IV IVH and/or PVL, nine (1%) with seizures and/or HIE, 91 (10%) with BPD, 57 (7%) with sepsis, 21 (2%) with NEC, and 361 (41%) who remained in the NICU > 7 days. In addition, 270 (31%) pregnancies were delivered by Cesarean section for non-reassuring fetal status, 43 (5%) were admitted to the NICU for < 7 days, 79 (9%) had 5-min Apgar score < 7, 125/631 (20%) had a cord gas pH ≤ 7.1 and 35/631 (6%) had a base excess ≥ 12 mmol/L. The predictive index we developed included seven factors available at the time of FGR diagnosis: hypertensive disorder of pregnancy (HDP) (+8 points), chronic hypertension without HDP (+4 points), gestational age ≤ 32 weeks (+5 points), absent or reversed end-diastolic flow in the umbilical artery (+8 points), prepregnancy body mass index ≥ 35 kg/m2 (+3 points), isolated abdominal circumference < 3rd  percentile (-4 points) and non-Hispanic black race (-2 points). The bias-corrected bootstrapped (1000 replicates) area under the receiver-operating-characteristics curve (AUC) of the predictive index for composite APO in the validation group was 0.88 (95% CI, 0.84-0.92), which was similar to that in the development group (AUC, 0.86 (95% CI, 0.82-0.89); P = 0.34). In the total cohort, 40% of pregnancies had a low-risk index score (≤ 2), associated with a NPV of 85% (95% CI, 81-88%) and a LR- of 0.21 (95% CI, 0.16-0.27), and 23% had a high-risk index score (≥ 10), associated with a PPV of 96% (95% CI, 93-98%) and a LR+ of 27.36 (95% CI, 14.33-52.23). Of the remaining pregnancies that had an intermediate-risk score, 50% were complicated by composite APO.

CONCLUSION

An easy-to-use index incorporating seven clinical factors readily available at the time of FGR diagnosis is predictive of APO and may prove useful in counseling and management of pregnancies meeting the ISUOG-endorsed criteria for FGR. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Adverse Neonatal Outcome of Pregnancies Complicated by Preeclampsia

Despite many available treatments, infants born to preeclamptic mothers continue to pose a serious clinical problem. The present study focuses on the evaluation of infants born to preeclamptic mothers for the occurrence of early-onset complications and attempts to link the clinical status of such infants to the angiogenesis markers in maternal blood (sFlt-1, PlGF). The study included 77 newborns and their mothers diagnosed with preeclampsia. The infants were assessed for their perinatal outcomes, with an emphasis on adverse neonatal outcomes such us infections, RDS, PDA, NEC, IVH, ROP, or BPD during the hospitalization period. The cutoff point was established using the ROC curve for the occurrence of any adverse neonatal outcome and it was 204 for the sFlt-1/PlGF and 32 birth week with AOC 0.644 and 0.91, respectively. The newborns born to mothers with high ratios had longer hospitalization times and, generally, were more frequently diagnosed with any of the aforementioned adverse neonatal outcomes. Also, the neonates born prior to or at 32 wkGA with higher sFlt-1/PlGF ratios were statistically significantly more common to be diagnosed with any of the adverse neonatal outcomes compared to those with lower ratio born prior to or at 32 wkGA. The sFlt-1/PlGF ratio can be a useful tool in predicting short-term adverse neonatal outcomes. Infants born after a full 33 weeks gestation developed almost no severe neonatal complications. Appropriate screening and preventive healthcare for preeclampsia can contribute significantly to reducing the incidence of neonatal complications.

Personalized Model to Predict Small for Gestational Age at Delivery Using Fetal Biometrics, Maternal Characteristics, and Pregnancy Biomarkers: A Retrospective Cohort Study of Births Assisted at a Spanish Hospital

Small for gestational age (SGA) is defined as a newborn with a birth weight for gestational age < 10th percentile. Routine third-trimester ultrasound screening for fetal growth assessment has detection rates (DR) from 50 to 80%. For this reason, the addition of other markers is being studied, such as maternal characteristics, biochemical values, and biophysical models, in order to create personalized combinations that can increase the predictive capacity of the ultrasound. With this purpose, this retrospective cohort study of 12,912 cases aims to compare the potential value of third-trimester screening, based on estimated weight percentile (EPW), by universal ultrasound at 35−37 weeks of gestation, with a combined model integrating maternal characteristics and biochemical markers (PAPP-A and β-HCG) for the prediction of SGA newborns. We observed that DR improved from 58.9% with the EW alone to 63.5% with the predictive model. Moreover, the AUC for the multivariate model was 0.882 (0.873−0.891 95% C.I.), showing a statistically significant difference with EPW alone (AUC 0.864 (95% C.I.: 0.854−0.873)). Although the improvements were modest, contingent detection models appear to be more sensitive than third-trimester ultrasound alone at predicting SGA at delivery.

Biophysical Markers of Suspected Preeclampsia, Fetal Growth Restriction and the Two Combined—How Accurate They Are?

Objectives—To conduct a secondary analysis of prediction accuracy of biophysical markers for suspected Preeclampsia (PE), Fetal Growth Restriction (FGR) and the two combined near delivery in a Slovenian cohort. Methods—This was a secondary analysis of a database of a total 125 Slovenian pregnant women attending a high-risk pregnancy clinic due to suspected PE (n = 31), FGR (n = 16) and PE + FGR (n = 42) from 28–39 weeks gestation and their corresponding term (n = 21) and preterm (PTD, n = 15) controls. Data for Mean Arterial blood Pressure (MAP) and Uterine artery pulsatility index (UtA PI) estimated by Doppler sonography were extracted from the database of patients who were tested at admission to the high-risk clinic with the suspected complications. The reactive hyperemia index (RHI), and the Augmentation Index (AIX%) were extracted from the patient database using measured values obtained with the assistance of the Endo PAT, a device set to measure the signal of the peripheral arterial tone (PAT) from the blood vessels endothelium. Linear regression coefficients, Box and Whisker plots, Area under the Curve (AUC) of receiver Operation Characteristic (ROC) curves, and multiple regression were used to assess the marker accuracy using detection rate (DR) and false-positive rate (FPR) and previously reported cut-offs for estimating the positive and negative predictive value (NPV and PPV). The SPSS non-parametric statistics (Kruskal Wallis and Mann–Whitney) and Spearman’s regression coefficient were used to assess marker accuracy; p < 0.05 was considered significant. Results—MAP values reached diagnostic accuracy (AUC = 1.00, DR = 100%) for early PE cases delivered < 34, whereas UtA Doppler PI values yielded such results for early FGR < 34 weeks and the two combined reached such accuracy for PE + FGR. To reach diagnostic accuracy for all cases of the complications, the Endo PAT markers with values for MAP and UtA Doppler PI were required for cases near delivery. Multiple regression analyses showed added value for advanced maternal age and gestational week in risk assessment for all cases of PE, FGR, and PE + FGR. Spearman’s regression coefficient yielded r > 0.6 for UtA Doppler PI over GA for PE and FGR, whereas for RHI over BMI, the regression coefficient was r > 0.5 (p < 0.001 for each). Very high correlations were also found between UtA Doppler PI and sFlt-1/PlGF or PlGF (r = −0.495, p < 0.001), especially in cases of FGR. Conclusion—The classical biophysical markers MAP and UtA Doppler PI provided diagnostic accuracy for PE and FGR < 34 wks gestation. A multiple biophysical marker analysis was required to reach diagnostic accuracy for all cases of these complications. The UtA Doppler PI and maternal serum sFlt-1/PlGF or PlGF were equally accurate for early cases to enable the choice of the markers for the clinical use according to the more accessible method.

Placental growth factor level is correlated with intrapartum fetal heart rate findings

Objective

Here, we tested the correlation between maternal placental growth factor (PlGF) and fetal heart rate (FHR) monitoring findings.

Methods

We included 35 women with single pregnancies from 35 to 42 weeks of gestation who were hospitalized owing to onset of labor. Blood samples were collected at the start of labor. Intrapartum FHR monitoring parameters included total deceleration area, average deceleration area (mean deceleration area per 10 min), and five-tier classification level.

Results

Of the 35 women, 26 (74%) had vaginal delivery and 9 (26%) had cesarean section. After excluding 2 women who had cesarean section for arrest of labor, we analyzed 26 women who had vaginal delivery (VD group) and 7 who had cesarean section for fetal indications (CSF group). PlGF level was significantly higher in the VD group (157 ± 106 pg/ml) than in the CSF group (74 ± 62 pg/ml) (P = 0.03). There were no significant correlations between PlGF and total (r = -0.07) or average (r = -0.08) deceleration area.　There was a significant negative correlation (r = -0.42, P = 0.01) between PlGF and the percentage of level 3 or higher in the five-level classification.

Conclusion

PlGF was correlated with FHR monitoring findings and might be a promising biomarker of intrapartum fetal function.

sFlt-1/PlGF Ratio in Prediction of Short-Term Neonatal Outcome of Small for Gestational Age Neonates

BACKGROUND

Small for gestational age is a pregnancy complication associated with a variety of adverse perinatal outcomes. The aim of the study was to investigate if sFlt-1/PlGF ratio is related to adverse short-term neonatal outcome in neonates small for gestational age in normotensive pregnancy.

METHODS

A prospective observational study was conducted. Serum sFlt-1/PlGF ratio was measured in women in singleton gestation diagnosed with fetus small for gestational age. Short-term neonatal outcome analyzed in the period between birth and discharge home.

RESULTS

Eighty-two women were included. Women with sFlt-1/PlGF ratio ≥33 gave birth to neonates with lower birthweight at lower gestational age. Neonates from high ratio group suffered from respiratory disorders and NEC significantly more often. They were hospitalized at NICU more often and were discharged home significantly later. sFlt-1/PlGF ratio predicted combined neonatal outcome with sensitivity of 73% and specificity of 82.2%.

CONCLUSIONS

sFlt-1/PlGF ratio is a useful toll in prediction of short-term adverse neonatal outcome in SGA pregnancies.

Fetal umbilical artery Doppler as a tool for universal third trimester screening: A systematic review and meta-analysis of diagnostic test accuracy

The objective of this study was to investigate the accuracy of universal third trimester umbilical artery (UA) Doppler to predict adverse pregnancy outcome at term. We searched Medline, EMBASE, the Cochrane library and ClinicalTrials.gov from inception to October 2020 and we also analyzed previously unpublished data from a prospective cohort study of nulliparous women, the Pregnancy Outcome Prediction (POP) study. We included studies that performed a third-trimester ultrasound scan in unselected, low or mixed risk populations, excluding studies which only included high risk pregnancies. Meta-analysis was performed using the hierarchal summary receiver operating characteristic curve (HSROC) analysis and bivariate logit-normal models. We identified 13 studies (including the POP study) involving 67,764 pregnancies which met our inclusion criteria. The overall quality was variable and only six studies (N = 5777 patients) blinded clinicians to the UA Doppler result. The summary sensitivity and positive likelihood ratio (LR) for small for gestational age (SGA; birthweight <10th centile) were 21.7% (95% CI 13.2-33.6%) and 2.65 (95% CI 1.89-3.72) respectively. The summary positive LR for NICU admission and metabolic acidosis were 1.35 (95% CI 0.93-1.97) and 1.34 (95% CI 0.86-2.08) respectively. The results were similar in the POP study: associations with SGA (positive LR 2.66 [95% CI 2.11-3.36]) and severe SGA (birthweight <3rd centile; positive LR 3.27 [95% CI 2.29-4.68]) but no statistically significant association with neonatal morbidity. We conclude that third trimester UA Doppler has moderate predictive accuracy for small for gestational age but not for indicators of neonatal morbidity in unselected and low risk pregnancies.

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.

Prediction of adverse perinatal outcome and the mean time until delivery in twin pregnancies with suspected pre-eclampsia using sFlt-1/PIGF ratio

PURPOSE

An elevated soluble fms-like tyrosine kinase-1 (sFlt-1) / placental growth factor (PlGF) ratio is associated with adverse perinatal outcome (APO) and the mean time until delivery (MTUD) in singleton pregnancies complicated by pre-eclampsia (PE). Data on APO and MTUD prediction in twin pregnancies using sFlt-1/PlGF ratio are scarce. We evaluated the predictive value of the sFlt-1/PIGF ratio regarding APO and MTUD in twin pregnancies with suspected PE and/or HELLP syndrome.

METHODS

This is a single center retrospective cohort study. All twin pregnancies with suspected PE/HELLP and determined sFlt-1/PIGF were included. Composite APO (CAPO) was defined as the presence of at least one of the following outcomes: respiratory distress syndrome (RDS), intubation, admission to neonatal intensive care unit (NICU) and arterial umbilical cord pH value < 7.10. Selective fetal growth restriction (s-FGR) was analyzed separately.

RESULTS

For final analysis, 49 twin pregnancies were included. Median sFlt-1/PIGF ratio was not significantly different in patients with CAPO compared to those without (89.45 vs. 62.00, p = 0.669). MTUD was significantly negative correlated with sFlt-1/PIGF ratio (r = -0.409, p < 0.001). For the whole study cohort, ROC analysis revealed no predictive value for sFlt-1/PIGF and CAPO (AUC = 0.618, 95% CI: 0.387-0.849, p = 0.254). However, sFlt-1/PIGF ratio showed a predictive value for s-FGR (AUC = 0.755, 95% CI: 0.545-0.965, p = 0.032).

CONCLUSION

In twin pregnancies with PE and/or HELLP, sFlt-1/PIGF ratio may be helpful for s-FGR prediction and decision-making regarding close monitoring of high-risk patients. However, further prospective studies are warranted to define the role of sFlt-1/PlGF ratio as outcome predictor in twin pregnancies.

Sex differences in uterine artery Doppler during gestation in pregnancies complicated by placental dysfunction

BACKGROUND

There is growing evidence of sex differences in placental vascular development. The objective of this study was to investigate the effect of fetal sex on uterine artery pulsatility index (PI) throughout gestation in a cohort of normal and complicated pregnancies.

METHODS

A prospective longitudinal study was conducted in 240 pregnant women. Pulsed wave Doppler ultrasound of the proximal uterine arteries was performed at a 4-weekly interval between 14 and 40 weeks of gestation. The patients were classified retrospectively as normal or complicated (one or more of maternal preeclampsia, preterm birth, or small for gestational age). To assess if the change in uterine artery PI during gestation differed between normal and complicated pregnancies and between fetal sexes, the uterine artery PI was modeled using a linear function of gestational age and the rate of change was estimated from the slope.

RESULTS

While the uterine artery PI did not differ over gestation between females and males for normal pregnancies, the trajectory of this index differed by fetal sex for pregnancies complicated by either preeclampsia, preterm birth, or fetal growth restriction (p < 0.0001). The male fetuses in the complicated pregnancy group had an elevated slope compared to the other groups (p < 0.0001), suggesting a more progressive deterioration in uteroplacental perfusion over gestation.

CONCLUSIONS

The uterine artery PI is widely used to assess uteroplacental function in clinical settings. The observation that this metric changes more rapidly in complicated pregnancies where the fetus was male highlights the importance of sex when interpreting hemodynamic markers of placental maturation.

Universal late pregnancy ultrasound screening to predict adverse outcomes in nulliparous women: a systematic review and cost-effectiveness analysis

BACKGROUND

Currently, pregnant women are screened using ultrasound to perform gestational aging, typically at around 12 weeks' gestation, and around the middle of pregnancy. Ultrasound scans thereafter are performed for clinical indications only.

OBJECTIVES

We sought to assess the case for offering universal late pregnancy ultrasound to all nulliparous women in the UK. The main questions addressed were the diagnostic effectiveness of universal late pregnancy ultrasound to predict adverse outcomes and the cost-effectiveness of either implementing universal ultrasound or conducting further research in this area.

DESIGN

We performed diagnostic test accuracy reviews of five ultrasonic measurements in late pregnancy. We conducted cost-effectiveness and value-of-information analyses of screening for fetal presentation, screening for small for gestational age fetuses and screening for large for gestational age fetuses. Finally, we conducted a survey and a focus group to determine the willingness of women to participate in a future randomised controlled trial.

DATA SOURCES

We searched MEDLINE, EMBASE and the Cochrane Library from inception to June 2019.

REVIEW METHODS

The protocol for the review was designed a priori and registered. Eligible studies were identified using keywords, with no restrictions for language or location. The risk of bias in studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool. Health economic modelling employed a decision tree analysed via Monte Carlo simulation. Health outcomes were from the fetal perspective and presented as quality-adjusted life-years. Costs were from the perspective of the public sector, defined as NHS England, and the costs of special educational needs. All costs and quality-adjusted life-years were discounted by 3.5% per annum and the reference case time horizon was 20 years.

RESULTS

Umbilical artery Doppler flow velocimetry, cerebroplacental ratio, severe oligohydramnios and borderline oligohydramnios were all either non-predictive or weakly predictive of the risk of neonatal morbidity (summary positive likelihood ratios between 1 and 2) and were all weakly predictive of the risk of delivering a small for gestational age infant (summary positive likelihood ratios between 2 and 4). Suspicion of fetal macrosomia is strongly predictive of the risk of delivering a large infant, but it is only weakly, albeit statistically significantly, predictive of the risk of shoulder dystocia. Very few studies blinded the result of the ultrasound scan and most studies were rated as being at a high risk of bias as a result of treatment paradox, ascertainment bias or iatrogenic harm. Health economic analysis indicated that universal ultrasound for fetal presentation only may be both clinically and economically justified on the basis of existing evidence. Universal ultrasound including fetal biometry was of borderline cost-effectiveness and was sensitive to assumptions. Value-of-information analysis indicated that the parameter that had the largest impact on decision uncertainty was the net difference in cost between an induced delivery and expectant management.

LIMITATIONS

The primary literature on the diagnostic effectiveness of ultrasound in late pregnancy is weak. Value-of-information analysis may have underestimated the uncertainty in the literature as it was focused on the internal validity of parameters, which is quantified, whereas the greatest uncertainty may be in the external validity to the research question, which is unquantified.

CONCLUSIONS

Universal screening for presentation at term may be justified on the basis of current knowledge. The current literature does not support universal ultrasonic screening for fetal growth disorders.

FUTURE WORK

We describe proof-of-principle randomised controlled trials that could better inform the case for screening using ultrasound in late pregnancy.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42017064093.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 15. See the NIHR Journals Library website for further project information.

Umbilical and Middle Cerebral Artery Doppler Measurements in Fetuses With Congenital Heart Block

OBJECTIVES

In fetal congenital complete heart block, the slow fetal heart rate prolongs the diastolic phase of the cardiac cycle, which may affect Doppler measurements that are typically used to quantify placental function. We here describe the umbilical artery (UA) and middle cerebral artery (MCA) Dopplers in a cohort of fetuses with heart block, hypothesizing that values will be increased but nevertheless remain associated with placental function and fetal outcome.

METHODS

We retrospectively reviewed Doppler measurements of the UA and MCA pulsatility index (PI) and resistance index in fetuses with complete heart block. The cerebroplacental ratio (CPR) was calculated as a marker of central redistribution. Measurements were transformed to Z scores and compared between fetuses born with a normal weight (appropriate for gestational age [AGA]) to those with fetal growth restriction (FGR) and correlated with a composite adverse outcome consisting of FGR, fetal death, or preterm birth prior to 34 weeks' gestation.

RESULTS

Fifty-four fetuses were included. There were 36 (67%) live births, 8 (22%) stillbirths, and 10 (19%) pregnancy terminations. Of those born alive, 14 (39%) had FGR. The UA PI decreased with gestational age and was higher in FGR compared with AGA fetuses (P < .001). Twenty-three percent of AGA fetuses developed absent end-diastolic flow in the UA. The MCA PI did not change with gestation and did not differ between AGA and FGR fetuses. The CPR was lower in FGR than in AGA fetuses (-2.43 ± 0.85 vs -1.44 ± 1.04, P = .006). The UA PI and resistance index were strongly correlated with the composite adverse outcome (P < .001).

CONCLUSIONS

The UA and MCA PI are significantly elevated in fetuses with complete heart block. The UA Doppler indices and CPR nevertheless still reflect placental function. Longitudinal measurements may be useful in monitoring well-being in fetuses with heart block.

The ability of late pregnancy maternal tests to predict adverse pregnancy outcomes associated with placental dysfunction (specifically fetal growth restriction and pre-eclampsia): a protocol for a systematic review and meta-analysis of prognostic accuracy studies

BACKGROUND

Pre-eclampsia and being born small for gestational age are associated with significant maternal and neonatal morbidity and mortality. Placental dysfunction is a key pathological process underpinning these conditions; thus, markers of placental function have the potential to identify pregnancies ending in pre-eclampsia, fetal growth restriction, and the birth of a small for gestational age infant.

PRIMARY OBJECTIVE

To assess the predictive ability of late pregnancy (after 24 weeks' gestation) tests in isolation or in combination for adverse pregnancy outcomes associated with placental dysfunction, including pre-eclampsia, fetal growth restriction, delivery of a SGA infant (more specifically neonatal growth restriction), and stillbirth.

METHODS

Studies assessing the ability of biochemical tests of placental function and/or ultrasound parameters in pregnant women beyond 24 weeks' gestation to predict outcomes including pre-eclampsia, stillbirth, delivery of a SGA infant (including neonatal growth restriction), and/or fetal growth restriction will be identified by searching the following databases: EMBASE, MEDLINE, Cochrane CENTRAL, Web of Science, CINAHL, ISRCTN registry, UK Clinical Trials Gateway, and WHO International Clinical Trials Portal. Any study design in which the biomarker and ultrasound scan potential predictors have been assessed after 24 weeks' gestation but before diagnosis of outcomes (pre-eclampsia, fetal growth restriction, SGA (including neonatal growth restriction), and stillbirth) will be eligible (this would include randomized control trials and nested prospective case-control and cohort studies), and there will be no restriction on the background risk of the population. All eligible studies will be assessed for risk of bias using the modified QUADAS-2 tool. Meta-analyses will be undertaken using the ROC models to estimate and compare test discrimination and reclassification indices to test calibration. Validation will be explored by comparing consistency across studies.

DISCUSSION

This review will assess whether current published data reporting either a single or combination of tests in late pregnancy can accurately predict adverse pregnancy outcome(s) associated with placental dysfunction. Accurate prediction could allow targeted management and possible intervention for high-risk pregnancies, ultimately avoiding adverse outcomes associated with placental disease.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018107049.

Cytokine profiles in maternal serum are candidates for predicting an optimal timing for the delivery in early-onset fetal growth restriction

OBJECTIVE

We examined whether maternal serum cytokine profiles of mothers with early-onset fetal growth restriction (FGR) were associated with delivery within 2 weeks after sampling during the third trimester.

STUDY DESIGN

This exploratory prospective cross-sectional study included a total of 20 singleton fetuses with early-onset FGR and 31 healthy controls. Maternal serum samples during the early third trimester were analyzed for 23 cytokines.

RESULTS

Of 20 fetuses with early-onset FGR, 14 had delivery within 2 weeks after sampling. Multivariate analysis revealed that maternal serum concentrations of soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) and soluble CD40 ligand (sCD40L) were independently associated with delivery within 2 weeks in early-onset FGR. Among cases of early-onset FGR, concentrations of almost all maternal serum cytokines were similar. Maternal serum sVEGFR-1 concentrations were high when delivery occurred within 2 weeks. Maternal serum sCD40L concentrations were elicited only in cases in which delivery within 2 weeks occurred due to fetal deterioration.

CONCLUSION

We identified two biomarkers, one specific for FGR and the other dependent on severity, that were significant components of angiogenic activities and inflammation factors. Imbalances in serum protein expression may have a substantial effect on the pathogenesis of FGR.

Association between antenatal maternal anxiety and fetal middle cerebral artery Doppler depends on fetal gender

Objective: Several studies have demonstrated that antenatal maternal anxiety (AMA) during pregnancy is associated with an increased risk of abnormal fetal Doppler parameters and adverse perinatal outcomes. Despite these studies, the evidence of the association between them remains inconclusive due in part to the methodological limitations of existing studies. Hence, in the present study, we established strict criteria and excluded patients who may have moderate or confounding variables to investigate the relationship between AMA and fetal Doppler findings and adverse perinatal outcomes.Methods: This was a cross-sectional study of 160 healthy nulliparous pregnant women (gestational age 31-33 weeks) with uncomplicated obstetric histories, who underwent Doppler flow studies on uterine, umbilical and fetal middle cerebral artery (MCA). Maternal anxiety was measured by STAI-State and STAI-Trait inventory.Results: Statistical analyses revealed that STAI-Trait anxiety was associated with lower MCA pulsatility index at 31-33 weeks gestational age and lower birth weight for the female fetus. There were no significant differences in the birth weight of boys of mothers with high anxiety and without high anxiety.Conclusions: The adaptation of the fetus to this hostile environment as AMA differs by gender. Adaptation for the female fetus means the "brain sparing effect" and reduced birth weight. The findings emphasize the potential importance of maternal psychological wellbeing during pregnancy for fetal development.

Establishing a Differential Marker Profile for Pregnancy Complications Near Delivery

OBJECTIVE

The aim of this work was to define a differential marker profile for pregnancy complications near delivery.

METHODS

We enrolled pregnant women who were referred to the outpatient pregnancy clinic of the University Medical Center, Ljubljana, Slovenia, due to symptoms of pregnancy complications and women with a history of pregnancy complications attending the high-risk hospital clinic for close surveillance. They were evaluated for prior risk and were tested for biophysical and biochemical markers at the time of enrolment. Biochemical markers included the pro- and anti-angiogenic markers, along with additional previously reported markers of potential value, all tested by various formats of immuno-diagnostics. Biophysical markers included blood pressure, sonographic markers, and EndoPAT. Statistical differences were determined with Kruskal-Wallis and Mann-Whitney tests for continuous parameters, and Pearson χ2 for categorical values. p < 0.05 was considered significant.

RESULTS

The cohort included 125 pregnant patients, 31 developed preeclampsia (PE) alone (13 were <34 weeks' gestation), 16 had intrauterine growth restriction (IUGR) alone (12 were <34 weeks), 42 had both IUGR and PE (22 were <34 weeks), and 15 had an iatrogenic preterm delivery (PTD; 6 were <34 weeks). Twenty-one were unaffected and delivered a healthy baby at term. Mean arterial blood pressure and proteinuria were significantly higher in PE and PE+IUGR but not in pure IUGR or PTD. In PE, IUGR, and PE+IUGR, the levels of soluble fms-like tyrosine kinase 1 (sFlt-1) and soluble endoglin (sEng) were significantly higher, while placental growth factor (PlGF) was very low compared to unaffected controls and PTD. PE, IUGR, and PE+IUGR also had a high anti-angiogenic ratio (sFlt-1/PlGF) and a low proangiogenic ratio of PlGF/(sFlt-1+Eng). Levels of inhibin A were significantly higher in pure PE across subgroups but had many extreme values, which made it a poor differentiator. Higher uterine artery Doppler pulsatility indexes were detected in PE, IUGR, and PE+IUGR, with similar resistance indexes and peaks of systolic velocity. A significantly different marker level between PE and IUGR was found using arterial stiffness that was 10 times higher in PE; concurrently with an increase of the reactive hyperemia index, both were accompanied by a slight increase in placental protein 13. Higher tumor necrosis factor alpha (TNFα) differentially identified iatrogenic very early PTD (<34 weeks).

CONCLUSION

Arterial stiffness can serve as a major marker to differentiate PE (with/without IUGR) from pure IUGR near delivery. TNFα can differentiate iatrogenic early PTD from other complications of pregnancy and term IUGR.

Role of sFlt-1 and PlGF in the screening of small-for-gestational age neonates during pregnancy: A systematic review

Background

Fetal growth restriction, i.e. the restriction of genetically predetermined growth potential due to placental dysfunction, is a major cause of neonatal morbidity and mortality. The consequences of inadequate fetal growth can be life-long, but the risks can be reduced substantially if the condition is identified prenatally. Currently, screening strategies are based on ultrasound detection of a small-for-gestational age fetus and do not take into account the underlying vascular pathology in the placenta. Measurement of maternal circulating angiogenic biomarkers placental growth factor, sFlt-1 (soluble FMS-like tyrosine kinase-1) are increasingly used in studies on fetal growth restriction as they reflect the pathophysiological process in the placenta. However, interpretation of the role of angiogenic biomarkers in prediction of fetal growth restriction is hampered by the varying design, population, timing, assay technique and cut-off values used in these studies.

Methods

We conducted a systematic-review in PubMed (MEDLINE), EMBASE (Ovid) and Cochrane to explore the predictive performance of maternal concentrations of placental growth factor, sFlt-1 and their ratio for fetal growth restriction and small-for-gestational age, at different gestational ages, and describe the longitudinal changes in biomarker concentrations and optimal discriminatory cut-off values.

Results

We included 26 studies with 2514 cases with small-for-gestational age, 27 cases of fetal growth restriction, 582 cases mixed small-for-gestational age/fetal growth restriction and 29,374 reference. The largest mean differences for the two biomarkers and their ratio were found after 26 weeks of gestational age and not in the first trimester. The ROC-AUC varied between 0.60 and 0.89 with sensitivity and specificity matching the different cut-off values or a preset false-positive rate of 10%.

Conclusions

Most of the studies did not make a distinction between small-for-gestational age and fetal growth restriction, and therefore the small-for-gestational age group consists of fetuses with growth restriction and fetuses that are constitutionally normal. The biomarkers can be a valuable screening tool for small-for-gestational age pregnancies, but unfortunately, there is not yet a clear cut-off value to use for screening. More research is needed to see if these biomarkers are sufficiently able to differentiate growth restriction on their own and how these biomarkers in combination with other relevant clinical and ultrasound parameters can be used in clinical routine diagnostics.

The sFlt-1/PlGF ratio values within the <38, 38-85 and >85 brackets as compared to perinatal outcomes

Background Soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) are used as markers of preeclampsia. The aim of this paper was to assess the correlations between the sFlt-1/PlGF ratio values within the <38, 38-85 and >85 brackets and perinatal outcomes in pregnancies that require determination of these markers. Methods A total of 927 pregnant patients between 18 and 41 weeks' gestation suspected of or confirmed with any form of placental insufficiency (preeclampsia, intrauterine growth restriction [IUGR], gestational hypertension, HELLP syndrome, placental abruption) were included in the study. In each of the patients, the sFlt-1/PlGF ratio was calculated. Patients were divided into three groups according to the sFlt-1/PlGF ratio brackets of <38, 38-85 and >85. Results Significantly worse perinatal outcomes were found in the sFlt-1/PlGF >85 group, primarily with lower cord blood pH, neonatal birth weight and shorter duration of gestation. Statistically significant correlations between the values of these markers and the abovementioned perinatal effects were found. Conclusion An sFlt-1/PlGF ratio value of >85 suggests that either preeclampsia or one of the other placental insufficiency forms may occur, which is associated with lower cord blood pH, newborn weight and earlier delivery. Determining the disordered angiogenesis markers and calculating the sFlt-1/PlGF ratio in pregnancies complicated by placental insufficiency may lead to better diagnosis, therapeutic decisions and better perinatal outcomes.

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.

Blood-based biomarkers in the maternal circulation associated with fetal growth restriction

Fetal growth restriction (FGR) is associated with threefold to fourfold increased risk of stillbirth. Identifying FGR, through its commonly used surrogate-the small-for-gestational-age (SGA, estimated fetal weight and/or abdominal circumference <10th centile) fetus-and instituting fetal surveillance and timely delivery decrease stillbirth risk. Methods available to clinicians for antenatal identification of SGA fetuses have surprisingly poor sensitivity. About 80% of cases remain undetected. Measuring the symphysis-fundal height detects only 20% of SGA fetuses, and even universal third trimester ultrasound detects, at best, 57% of those born SGA. There is an urgent need to find better ways to identify this at-risk cohort. This review summarises efforts to identify molecular biomarkers (proteins, metabolites, or ribonucleic acids) that could be used to better predict FGR. Most studies examining potential biomarkers to date have utilised case-control study designs without proceeding to validation in independent cohorts. To develop a robust test for FGR, large prospective studies are required with a priori validation plans and cohorts. Given that current clinical care detects 20% of SGA fetuses, even a screening test with ≥60% sensitivity at 90% specificity could be clinically useful, if developed. This may be an achievable aspiration. If discovered, such a test may decrease stillbirth.

Biomarkers of impaired placentation at 35-37 weeks' gestation in the prediction of adverse perinatal outcome

OBJECTIVE

To investigate the potential value of uterine artery pulsatility index (UtA-PI) and serum levels of the angiogenic placental growth factor (PlGF) and the antiangiogenic factor soluble fms-like tyrosine kinase-1 (sFlt-1) in the prediction of adverse perinatal outcome in small-for-gestational-age (SGA) and non-SGA neonates at 35-37 weeks' gestation.

METHODS

This was a prospective observational study of 19 209 singleton pregnancies attending for a routine hospital visit at 35 + 0 to 36 + 6 weeks' gestation. This visit included recording of maternal demographic characteristics and medical history, sonographic estimation of fetal weight, color Doppler ultrasound for measurement of mean UtA-PI, and measurement of serum concentrations of PlGF and sFlt-1. Multivariable logistic regression analysis was carried out to determine which of the factors from maternal or pregnancy characteristics and measurements of UtA-PI, PlGF and sFlt-1 provided a significant contribution in the prediction of each of four adverse outcome measures: first, stillbirth; second, Cesarean delivery for suspected fetal compromise in labor; third, neonatal death or hypoxic ischemic encephalopathy Grade 2 or 3; and, fourth, admission to the neonatal unit (NNU) for ≥ 48 h. Predicted probabilities from logistic regression analysis were used to construct receiver-operating characteristics curves to assess the performance of screening for these adverse outcomes.

RESULTS

First, 83% of stillbirths, 82% of Cesarean sections for presumed fetal compromise in labor, 91% of cases of neonatal death or hypoxic ischemic encephalopathy and 86% of NNU admissions for ≥ 48 h occurred in pregnancies with a non-SGA neonate. Second, UtA-PI > 95^th percentile, sFlt-1 > 95^th percentile and PlGF < 5^th percentile were associated with increased risk of Cesarean delivery for suspected fetal compromise in labor and NNU admission for ≥ 48 h; the number of stillbirths and cases of neonatal death or hypoxic ischemic encephalopathy was too small to demonstrate significance in the observed differences from cases without these adverse outcomes. Third, multivariable logistic regression analysis demonstrated that, in the prediction of Cesarean delivery for suspected fetal compromise in labor, there was no significant contribution from biomarkers; the prediction of NNU admission for ≥ 48 h by maternal demographic characteristics and medical history was only marginally improved by the addition of sFlt-1 or PlGF. Fourth, for each biomarker, the detection rate of adverse outcome was higher in SGA than in non-SGA neonates, but this increase was accompanied by an increase in false-positive rate. Fifth, the relative risk of UtA-PI > 95^th , sFlt-1 > 95^th and PlGF < 5^th percentiles for most adverse outcomes was < 2.5 in both SGA and non-SGA neonates.

CONCLUSIONS

In pregnancies undergoing routine antenatal assessment at 35-37 weeks' gestation, measurements of UtA-PI, sFlt-1 or PlGF provide poor prediction of adverse perinatal outcome in both SGA and non-SGA fetuses. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Detection of Adverse Perinatal Outcomes at Term Delivery Using Ultrasound Estimated Percentile Weight at 35 Weeks of Gestation: Comparison of Five Fetal Growth Standards

OBJECTIVE

To assess the predictive ability of the ultrasound estimated percentile weight (EPW) at 35 weeks of pregnancy to predict adverse perinatal outcomes (APOs) at term delivery according to 5 fetal growth standards, including population, population-customized, and international references.

METHODS

This was a retrospective cohort study of 9,585 singleton pregnancies. Maternal clinical characteristics, fetal ultrasound data obtained at 35 weeks and pregnancy and perinatal outcomes were used to calculate EPWs to predict APOs according to: the customized and noncustomized (NC) Miguel Servet University Hospital (MSUH), the customized Figueras, the NC INTERGROWTH-21st, and the NC World Health Organization (WHO) international standards. APOs were defined as the occurrence of cesarean or instrumental delivery for nonreassuring fetal status, 5-min Apgar score < 7, arterial cord blood pH <7.10, or stillbirth. The predictive ability of EPW for APOs was analyzed using the area under the curve (AUC), and sensitivities were calculated for different false-positive rates (FPRs).

RESULTS

For a 10% FPR, detection rates for total APOs ranged between 12.7% with the customized MSUH (AUC 0.52; 95% CI 0.50-0.55) and 14.4% with the NC MSUH standard (AUC 0.55; 95% CI 0.53-0.57) for EPW by ultrasound; and from 22.0% with the customized MSUH standard (AUC 0.60; 95% CI 0.58-0.63) to 27.8% with the NC WHO (AUC 0.65; 95% CI 0.63-0.68) for EPW at delivery.

CONCLUSIONS

The predictive capacity of the EPW for APOS is limited and similar, by both ultrasound and at delivery, for the 5 growth standards, without significant differences between customized and NC standards.

Reference Centile Chart of Fetal Cerebroplacental Doppler from 24 to 40 Weeks Gestation in Indian Population

Objective

Construction of reference centile chart of middle cerebral (MCA) and umbilical artery (UA) Doppler along with cerebroplacental ratio from 24 to 40 weeks gestation in Indian population.

Method

It was a cross-sectional observational study; antenatal women between 24 and 40 weeks gestation underwent the MCA and UA Doppler. The centile charts for MCA, UA and cerebroplacental ratio (CPR) were derived.

Results

Total 300 antenatal women were included; the MCA PI, RI, S/D ratio values showed a parabolic curve with the peak at 33-35 weeks; the umbilical artery Doppler and cerebroplacental ratio showed a linear decrease with increasing gestational age. The regression analysis showed a weak correlation between the Doppler parameters and the gestational age. The MOM values of all Doppler parameters, across the gestational age, were also derived.

Conclusion

The constructed MCA, UA and CPR charts along with their MOM values could be used as reference for the regional population.

Diagnostic performance of third-trimester ultrasound for the prediction of late-onset fetal growth restriction: a systematic review and meta-analysis

OBJECTIVE

The objective of the study was to establish the diagnostic performance of ultrasound screening for predicting late smallness for gestational age and/or fetal growth restriction.

DATA SOURCES

A systematic search was performed to identify relevant studies published since 2007 in English, Spanish, French, Italian, or German, using the databases PubMed, ISI Web of Science, and SCOPUS.

STUDY ELIGIBILITY CRITERIA

We used rrospective and retrospective cohort studies in low-risk or nonselected singleton pregnancies with screening ultrasound performed at ≥32 weeks of gestation.

STUDY APPRAISAL AND SYNTHESIS METHODS

The estimated fetal weight and fetal abdominal circumference were assessed as index tests for the prediction of birthweight <10th (i.e. smallness for gestational age), less than the fifth, and less than the third centile and fetal growth restriction (estimated fetal weight less than the third or estimated fetal weight <10th plus Doppler signs). Quality of the included studies was independently assessed by 2 reviewers, using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. For the meta-analysis, hierarchical summary receiver-operating characteristic curves were constructed, and quantitative data synthesis was performed using random-effects models. The sensitivity of the abdominal circumference <10th centile and estimated fetal weight <10th centile for a fixed 10% false-positive rate was derived from the corresponding hierarchical summary receiver-operating characteristic curves. Heterogeneity between studies was visually assessed using Galbraith plots, and publication bias was assessed by funnel plots and quantified by Deeks' method.

RESULTS

A total of 21 studies were included. Observed pooled sensitivities of abdominal circumference and estimated fetal weight <10th centile for birthweight <10th centile were 35% (95% confidence interval, 20-52%) and 38% (95% confidence interval, 31-46%), respectively. Observed pooled specificities were 97% (95% confidence interval, 95-98%) and 95% (95% confidence interval, 93-97%), respectively. Modeled sensitivities of abdominal circumference and estimated fetal weight <10th centile for 10% false-positive rate were 78% (95% confidence interval, 61-95%) and 54% (95% confidence interval, 46-52%), respectively. The sensitivity of estimated fetal weight <10th centile was better when aimed to fetal growth restriction than to smallness for gestational age. Meta-regression analysis showed a significant increase in sensitivity when ultrasound evaluation was performed later in pregnancy (P = .001).

CONCLUSION

Third-trimester abdominal circumference and estimated fetal weight perform similar in predicting smallness for gestational age. However, for a fixed 10% false-positive rate extrapolated sensitivity is higher for abdominal circumference. There is evidence of better performance when the scan is performed near term and when fetal growth restriction is the targeted condition.

Fetal Medicine Foundation reference ranges for umbilical artery and middle cerebral artery pulsatility index and cerebroplacental ratio

OBJECTIVES

To develop gestational age-based reference ranges for the pulsatility index in the umbilical artery (UA-PI) and fetal middle cerebral artery (MCA-PI) and the cerebroplacental ratio (MCA-PI/UA-PI), and to examine the maternal characteristics and medical history that affect these measurements.

METHODS

This was a cross-sectional study of 72 387 pregnancies undergoing routine ultrasound examination at 20 + 0 to 22 + 6 weeks' gestation (n = 3712), 31 + 0 to 33 + 6 weeks (n = 29 035), 35 + 0 to 36 + 6 weeks (n = 37 252) or 41 + 0 to 41 + 6 weeks (n = 2388). For the purpose of this study, we included data for only one of the second- or third-trimester visits. The inclusion criteria were singleton pregnancy, dating by fetal crown-rump length at 11 + 0 to 13 + 6 weeks' gestation, live birth of a morphologically normal neonate and ultrasonographic measurements by sonographers who had received the Fetal Medicine Foundation Certificate of Competence in Doppler ultrasound. Since the objectives of the study were to establish reference ranges, rather than normal ranges, and to examine factors from maternal characteristics and medical history that affect these measurements, we included all pregnancies having routine ultrasound examinations, irrespective of whether the mother had a pre-existing medical condition, such as diabetes mellitus, or a pregnancy complication, such as pre-eclampsia or suspected fetal growth restriction. Median and SD models were fitted between UA-PI, MCA-PI and CPR and gestational age. Assessment of goodness of fit of the models was by inspection of quantile-to-quantile (Q-Q) plots of Z-scores calculated using the mean and SD models. The distributions of MCA-PI, UA-PI and CPR Z-scores were examined in relation to maternal characteristics and medical history.

RESULTS

The relationship between the median and gestational age was linear for UA-PI and cubic for MCA-PI and CPR and the SD was log quadratic for all three. MCA-PI and CPR increased with gestational age from 20 weeks' gestation to reach a peak at around 32 and 34 weeks, respectively, and decreased thereafter, whereas UA-PI decreased linearly with gestational age from 20 to 42 weeks. Compared to the general population, significant deviations in multiples of the median values of UA-PI, MCA-PI and CPR were observed in subgroups of maternal age, body mass index, racial origin, method of conception and parity.

CONCLUSION

This study established new reference ranges for UA-PI, MCA-PI and CPR, according to gestational age, and reports maternal characteristics and medical history that affect these measurements. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Prediction models for preeclampsia: A systematic review

BACKGROUND

Preeclampsia is a disease specific to pregnancy that can cause severe maternal and foetal morbidity and mortality. Early identification of women at higher risk for preeclampsia could potentially aid early prevention and treatment. Although a plethora of preeclampsia prediction models have been developed in recent years, individualised prediction of preeclampsia is rarely used in clinical practice.

OBJECTIVES

The objective of this systematic review was to provide an overview of studies on preeclampsia prediction.

STUDY DESIGN

Relevant research papers were identified through a MEDLINE search up to 1 January 2017. Prognostic studies on the prediction of preeclampsia or preeclampsia-related disorders were included. Quality screening was performed with the Quality in Prognostic Studies (QUIPS) tool.

RESULTS

Sixty-eight prediction models from 70 studies with 425,125 participants were selected for further review. The number of participants varied and the gestational age at prediction varied widely across studies. The most frequently used predictors were medical history, body mass index, blood pressure, parity, uterine artery pulsatility index, and maternal age. The type of predictor (maternal characteristics, ultrasound markers and/or biomarkers) was not clearly associated with model discrimination. Few prediction studies were internally (4%) or externally (6%) validated.

CONCLUSIONS

To date, multiple and widely varying models for preeclampsia prediction have been developed, some yielding promising results. The high degree of between-study heterogeneity impedes selection of the best model, or an aggregated analysis of prognostic models. Before multivariable preeclampsia prediction can be clinically implemented universally, further validation and calibration of well-performing prediction models is needed.

Risk of operative delivery for intrapartum fetal compromise in small-for-gestational-age fetuses at term: external validation of the IRIS algorithm

Objectives: Small-for-gestational-age fetuses (SGA) are at high risk of intrapartum fetal compromise requiring operative delivery. In a recent study, we developed a model using a combination of three antenatal (gestational age at delivery, parity, cerebroplacental ratio) and three intrapartum (epidural use, labor induction and augmentation using oxytocin) variables for the prediction of operative delivery due to presumed fetal compromise in SGA fetuses - the Individual RIsk aSsessment (IRIS) prediction model. The aim of this study was to test the predictive accuracy of the IRIS prediction model in an external cohort of singleton pregnancies complicated by SGA.Methods: This was an external validation study using a cohort of pregnancies from two tertiary referral centers in Spain and England. The inclusion criteria were singleton pregnancies diagnosed with an SGA fetus, defined as estimated fetal weight (EFW) below the 10th centile for gestational age at 36 weeks or beyond, which had fetal Doppler assessment and available data on their intrapartum care and pregnancy outcomes. The main outcome in this study was the operative delivery for presumed fetal compromise. External validation was performed using the coefficients obtained in the original development cohort. The predictive accuracies of models were investigated with receiver operating characteristics (ROC) curves. The Hosmer-Lemeshow test was used to test the goodness-of-fit of models and calibration plots were also obtained for visual assessment. A mobile application using the combined model algorithm was developed to facilitate clinical use.Results: Four hundred twelve singleton pregnancies with an antenatal diagnosis of SGA were included in the study. The operative delivery rate was 22.8% (n = 94). The group which required operative delivery for presumed fetal compromise had significantly fewer multiparous women (19.1 versus 47.8%, p < .001 in the total study population; 19.0 versus 43.5 and 19.2 versus 49.6%, UK and Spain cohort, respectively), lower cerebroplacental ratio (CPR) multiples of median (MoM) (median: 0.77 versus 0.92, p < .001 in the total study population; 0.77 versus 0.92 and 0.77 versus 0.92, UK and Spain cohort, respectively), more inductions of labor (74.5 versus 60.1%, p = .010 in the total study population; 85.7 versus 77.2 and 71.2% and 53.1, UK and Spain cohort, respectively) and more use of oxytocin augmentation (57.4 versus 39.3%, p = .002 in the total study population; 19.0 versus 12.0 and 68.5 and 50.4%, UK and Spain cohort, respectively) compared to those who did not require operative delivery due to presumed fetal compromise. When the original antenatal model was applied to the present cohort, we observed moderate predictive accuracy (AUC: 0.70, 95% CI: 0.64-0.76), and no signs of poor fit (p = .464). The original combined model, when applied to the external cohort, had moderate predictive accuracy (AUC: 0.72, 95% CI: 0.67-0.77) and also no signs of poor fit (p = .268) without the need for refitting. A statistically significant increase in the predictive accuracy was not achieved via refitting of the combined model (AUC 0.76 versus 0.72, p = .060).Conclusions: Using our recently published model, the predictive accuracy for fetal compromise requiring operative delivery in term fetuses thought to be SGA was modest and showed no signs of poor fit in an external cohort. The IRIS tool for mobile devices has been developed to facilitate wide clinical use of this prediction model.Brief rationaleObjective: To determine the external validity of an intrapartum risk prediction model for suspected small-for-gestational age fetuses.What is already known: Small-for-gestational age fetuses are at increased risk of intrapartum compromise. Fetal weight alone is a poor marker for adverse outcomes and a comprehensive prediction model has been previously suggested.What this study adds: Multivariable prediction model showed good accuracy and calibration in this external validation study. The significance of some variables was different between the original and external validation cohort and there was a small margin for improvement with model refitting. A mobile application has been developed to facilitate clinical use.

Bemiparin as a Prophylaxis After an Unexplained Stillbirth: Open-Label Interventional Prospective Study

Stillbirth is a devastating event to the parents, relatives, friends, and families. The role of anticoagulants in the prevention of unexplained stillbirths is uncertain. An open-label interventional prospective cohort study was conducted on 144 women with a history of unexplained stillbirths. The intervention group had a high umbilical artery resistance index (RI) and received bemiparin. The nonintervention group had a normal RI and did not receive any intervention. We measured the adjusted odds ratio (OR) and 95% confidence interval (CI) of the main outcome for these variables using logistic regression analysis. Fresh stillbirth and early neonatal death rates were lower (P = .005, OR = 11.949 and 95% CI = 2.099-68.014) and newborn weight was higher (P = .015, OR = 0.048, 95% CI = 0.004-0.549) in the group that received bemiparin. Bemiparin is effective in decreasing the rate of stillbirth in women with a history of previous unexplained stillbirths.

Changes in intrapartum maternal placental growth factor levels in pregnancies complicated by fetal compromise at term

BACKGROUND

Intrapartum fetal compromise (IFC) may result from the gradual decline in placental function during labour and can precipitate adverse neonatal outcomes. Placental growth factor (PlGF) is a biomarker of placental function. This study aims to investigate maternal PlGF levels and adverse perinatal outcomes in term labour.

METHODS

Prospective observational study (Mater Mothers' Hospital, Brisbane). Eligibility: 37⁺⁰- 42⁺⁰ weeks gestation, singleton, cephalic, non-anomalous pregnancies. Cases of pre-eclampsia and fetal growth restriction were excluded. Maternal PlGF was sampled at the onset of the first stage of labour (1st PlGF) and again at the second stage (2nd PlGF).

RESULTS

Sixty-three participants met inclusion criteria. Women requiring operative delivery (n = 11) for IFC had lower 1st PlGF (90.8 vs. 111.8 pg/ml) and 2nd PlGF (65.8 vs. 83.7 pg/ml) compared to the no-IFC cohort (n = 52). PlGF levels decreased significantly during labour in both the IFC (90.8 vs. 65.8 pg/ml, p = 0.021) and no-IFC (111.8 v 83.7, p < 0.001) cohorts, although the decline in PlGF levels was greater in the IFC cohort (-41.8% vs. -23.4%, p = 0.385). Maternal PlGF levels were significantly lower in those with an abnormal fetal heart rate pattern, cord arterial pH < 7.2, nursery admission and composite adverse neonatal outcome (CANO). PlGF decline was not correlated to duration of labour but was influenced by nulliparity and induced labour.

CONCLUSIONS

Maternal PlGF levels are lower in pregnancies complicated by IFC and CANO, and declines more sharply during labour compared to the no-IFC cohort. The utility of PlGF as a predictor of IFC should be further investigated with clinical trials.

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.

Utility of Doppler parameters at 36-42 weeks' gestation in the prediction of adverse perinatal outcomes in appropriate-for-gestational-age fetuses

Aim

To investigate the potential value of Doppler ultrasound and to assess cerebroplacental ratio (CPR) in the prediction of adverse perinatal outcome defined as Apgar score < 7 at 1 minute.

Material and methods

This was a retrospective cross-sectional study in selected pregnant women undergoing an ultrasound examination between 36 and 42 weeks of gestation. We measured estimated fetal weight (EFW), mean umbilical artery pulsatility index (UA PI), mean middle cerebral artery pulsatility index (MCA PI), CPR, and Apgar score in 1 minute. Multiples of medians (MoM) were calculated for MCA PI and UA PI.

Results

The study group consisted of 446 women, 236 were primipara and 210 were multipara. The average age was 29.6 years (range 16–46 years). The average week of delivery is 39.5 weeks of gestation (range 36–42). Mean MCA PI and UA PI were 1.3 (0.1–2.45) and 0.8 (0.39–1.66), respectively. The mean values were 1.03 (0.1–1.9) for MCA PI MoM and 1.04 (0.5–2.1) for UA PI MoM. Primiparas had lower values of MCA PI (1.27 vs. 1.34), MCA PI MoM (1.00 vs. 1.05), CPR (1.62 vs. 1.73), EFW (3479.53 g vs. 3579.25 g) and birth weight (3513.50 g vs. 3617.79 g). For CPR cut-off point of 1.08: sensitivity was (0.945), specificity 0.1, positive predictive values 0.979, negative predictive values 0.04 and accuracy 0.926. The ROC curves for CPR were: area under the curve was 0.52 at CI 95% (0.342–0.698), p = 0.8271.

Conclusion

Screening in pregnancies with appropriate-for-gestational-age fetuses at 36–42 weeks of gestation using Doppler parameters is not useful in the prediction of adverse perinatal outcomes like an Apgar score < 7 at 1 minute.

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.