Essential variables for reporting research studies on fetal growth restriction: a Delphi consensus

Validity of a Delphi consensus definition of growth restriction in the newborn for identifying neonatal morbidity

BACKGROUND

Small for gestational age is defined as a birthweight below a birthweight percentile threshold, usually the 10th percentile, with the third or fifth percentile used to identify severe small for gestational age. Small for gestational age is used as a proxy for growth restriction in the newborn, but small-for-gestational-age newborns can be physiologically small and healthy. In addition, this definition excludes growth-restricted newborns who have weights more than the 10th percentile. To address these limits, a Delphi study developed a new consensus definition of growth restriction in newborns on the basis of neonatal anthropometric and clinical parameters, but it has not been evaluated.

OBJECTIVE

To assess the prevalence of growth restriction in the newborn according to the Delphi consensus definition and to investigate associated morbidity risks compared with definitions of Small for gestational age using birthweight percentile thresholds.

STUDY DESIGN

Data come from the 2016 and 2021 French National Perinatal Surveys, which include all births ≥22 weeks and/or with birthweights ≥500 g in all maternity units in France over 1 week. Data are collected from medical records and interviews with mothers after the delivery. The study population included 23,897 liveborn singleton births. The Delphi consensus definition of growth restriction was birthweight less than third percentile or at least 3 of the following criteria: birthweight, head circumference or length <10th percentile, antenatal diagnosis of growth restriction, or maternal hypertension. A composite of neonatal morbidity at birth, defined as 5-minute Apgar score <7, cord arterial pH <7.10, resuscitation and/or neonatal admission, was compared using the Delphi definition and usual birthweight percentile thresholds for defining small for gestational age using the following birthweight percentile groups: less than a third, third to fourth, and fifth to ninth percentiles. Relative risks were adjusted for maternal characteristics (age, parity, body mass index, smoking, educational level, preexisting hypertension and diabetes, and study year) and then for the consensus definition and birthweight percentile groups. Multiple imputation by chained equations was used to impute missing data. Analyses were carried out in the overall sample and among term and preterm newborns separately.

RESULTS

We identified that 4.9% (95% confidence intervals, 4.6-5.2) of newborns had growth restriction. Of these infants, 29.7% experienced morbidity, yielding an adjusted relative risk of 2.5 (95% confidence intervals, 2.2-2.7) compared with newborns without growth restriction. Compared with birthweight ≥10th percentile, morbidity risks were higher for low birthweight percentiles (less than third percentile: adjusted relative risk, 3.3 [95% confidence intervals, 3.0-3.7]; third to fourth percentile: relative risk, 1.4 [95% confidence intervals, 1.1-1.7]; fifth to ninth percentile: relative risk, 1.4 [95% confidence intervals, 1.2-1.6]). In adjusted models including the definition of growth restriction and birthweight percentile groups and excluding birthweights less than third percentile, which are included in both definitions, morbidity risks remained higher for birthweights at the third to fourth percentile (adjusted relative risk, 1.4 [95% confidence intervals, 1.1-1.7]) and fifth to ninth percentile (adjusted relative risk, 1.4 [95% confidence intervals, 1.2-1.6]), but not for the Delphi definition of growth restriction (adjusted relative risk, 0.9 [95% confidence intervals, 0.7-1.2]). Similar patterns were found for term and preterm newborns.

CONCLUSION

The Delphi consensus definition of growth restriction did not identify more newborns with morbidity than definitions of small for gestational age on the basis of birthweight percentiles. These findings illustrate the importance of evaluating the results of Delphi consensus studies before their adoption in clinical practice.

Cook's balloon versus dinoprostone for Labour induction of term pregnancies with fetal GROWth restriction: study protocol for a randomised controlled trial in tertiary maternity hospitals in Spain (COLIGROW study)

INTRODUCTION

Fetal growth restriction (FGR) affects about 3%-5% of term pregnancies. If prenatally detected and anterograde umbilical artery flow is preserved (stage I), it is recommended to deliver at term (≥ 37+0 weeks). In the absence of contraindications, the vaginal route is preferred, and labour induction is usually required. It has been postulated that mechanical methods for cervical ripening may have an optimal profile for the induction of term FGR fetuses since they are associated with less uterine stimulation than the standard pharmacological methods, and therefore, could be better tolerated by fetuses with reduced placental reserve. This study aims to evaluate whether cervical ripening with a Cook's balloon for the induction of labour from 37+0 weeks of gestation in the stage I FGR manages to increase the rate of vaginal delivery compared with vaginal dinoprostone.

METHODS AND ANALYSIS

This will be an open-labelled, randomised, parallel-group clinical trial to be held in five Spanish maternities. Women aged ≥18 years with singleton pregnancies complicated with stage I FGR (defined as the presence of at least one of these two criteria: (1) estimated fetal weight (EFW) <3rd percentile; (2) EFW <10th percentile and at least one of the following: (2.1.) umbilical artery pulsatility index >95th percentile and presence of antegrade end-diastolic flow or (2.2.) Cerebroplacental ratio <5th percentile), gestational age dated by first-trimester ultrasound ≥37+0 weeks at the time of labour induction, cephalic presentation, unfavourable cervix (Bishop score <7), intact fetal membranes, no previous caesarean section and no maternal or fetal contraindications for vaginal delivery or labour induction will be 1:1 randomised by centre to labour induction with Cook's balloon (experimental arm) or dinoprostone (control arm). FGR cases with evidence of non-placental origin (major structural fetal malformations, chromosomal anomalies or congenital infection) will be excluded. The primary outcome is the achievement of a vaginal delivery and it will be assessed by comparing the rates of vaginal delivery in each group using the one-sided χ2 test at an alpha level of 0.025. The sample size has been estimated to observe an expected 84% of vaginal deliveries with Cook's balloon vs 62% with dinoprostone. Therefore, a total of 172 patients (86 per arm) are required (power of 90%, alpha level of 0.025, assuming a percentage of losses of 5%). The efficacy analysis will be performed in the intention-to-treat population. An interim analysis using a two-stage sequential design with the O'Brien-Fleming method will be applied.

ETHICS AND DISSEMINATION

The trial was registered in the European Union drug regulating authorities' clinical trials database (EUDRACT) (2021-001726-22) and received approval from the local Research Ethics Committee (21/728) and the Spanish Agency of Medicines and Medical Devices (AEMPS). AEMPS classified the study as a low-intervention trial. The study will be conducted in compliance with the principles of Good Clinical Practice. The study results will be disseminated through workshops and national/international conferences and published in peer-reviewed journals. In addition, they will be disclosed to patients and the public in understandable language through study newsletters and press releases to news and social media.

PROTOCOL VERSION

V.1.1, 18 May 2023.

TRIAL REGISTRATION NUMBERS

EUDRACT 2021-001726-22 and NCT05774236.

Development and validation of prediction models for fetal growth restriction and birthweight: an individual participant data meta-analysis

Background

Fetal growth restriction is associated with perinatal morbidity and mortality. Early identification of women having at-risk fetuses can reduce perinatal adverse outcomes.

Objectives

To assess the predictive performance of existing models predicting fetal growth restriction and birthweight, and if needed, to develop and validate new multivariable models using individual participant data.

Design

Individual participant data meta-analyses of cohorts in International Prediction of Pregnancy Complications network, decision curve analysis and health economics analysis.

Participants

Pregnant women at booking. External validation of existing models (9 cohorts, 441,415 pregnancies); International Prediction of Pregnancy Complications model development and validation (4 cohorts, 237,228 pregnancies).

Predictors

Maternal clinical characteristics, biochemical and ultrasound markers.

Primary outcomes

fetal growth restriction defined as birthweight <10th centile adjusted for gestational age and with stillbirth, neonatal death or delivery before 32 weeks' gestation birthweight.

Analysis

First, we externally validated existing models using individual participant data meta-analysis. If needed, we developed and validated new International Prediction of Pregnancy Complications models using random-intercept regression models with backward elimination for variable selection and undertook internal-external cross-validation. We estimated the study-specific performance (c-statistic, calibration slope, calibration-in-the-large) for each model and pooled using random-effects meta-analysis. Heterogeneity was quantified using τ2 and 95% prediction intervals. We assessed the clinical utility of the fetal growth restriction model using decision curve analysis, and health economics analysis based on National Institute for Health and Care Excellence 2008 model.

Results

Of the 119 published models, one birthweight model (Poon) could be validated. None reported fetal growth restriction using our definition. Across all cohorts, the Poon model had good summary calibration slope of 0.93 (95% confidence interval 0.90 to 0.96) with slight overfitting, and underpredicted birthweight by 90.4 g on average (95% confidence interval 37.9 g to 142.9 g). The newly developed International Prediction of Pregnancy Complications-fetal growth restriction model included maternal age, height, parity, smoking status, ethnicity, and any history of hypertension, pre-eclampsia, previous stillbirth or small for gestational age baby and gestational age at delivery. This allowed predictions conditional on a range of assumed gestational ages at delivery. The pooled apparent c-statistic and calibration were 0.96 (95% confidence interval 0.51 to 1.0), and 0.95 (95% confidence interval 0.67 to 1.23), respectively. The model showed positive net benefit for predicted probability thresholds between 1% and 90%. In addition to the predictors in the International Prediction of Pregnancy Complications-fetal growth restriction model, the International Prediction of Pregnancy Complications-birthweight model included maternal weight, history of diabetes and mode of conception. Average calibration slope across cohorts in the internal-external cross-validation was 1.00 (95% confidence interval 0.78 to 1.23) with no evidence of overfitting. Birthweight was underestimated by 9.7 g on average (95% confidence interval -154.3 g to 173.8 g).

Limitations

We could not externally validate most of the published models due to variations in the definitions of outcomes. Internal-external cross-validation of our International Prediction of Pregnancy Complications-fetal growth restriction model was limited by the paucity of events in the included cohorts. The economic evaluation using the published National Institute for Health and Care Excellence 2008 model may not reflect current practice, and full economic evaluation was not possible due to paucity of data.

Future work

International Prediction of Pregnancy Complications models' performance needs to be assessed in routine practice, and their impact on decision-making and clinical outcomes needs evaluation.

Conclusion

The International Prediction of Pregnancy Complications-fetal growth restriction and International Prediction of Pregnancy Complications-birthweight models accurately predict fetal growth restriction and birthweight for various assumed gestational ages at delivery. These can be used to stratify the risk status at booking, plan monitoring and management.

Study registration

This study is registered as PROSPERO CRD42019135045.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: 17/148/07) and is published in full in Health Technology Assessment; Vol. 28, No. 14. See the NIHR Funding and Awards website for further award information.

The association between discordant umbilical arterial resistance in growth-restricted fetuses and adverse outcomes

BACKGROUND

Assessing the umbilical artery pulsatility index via Doppler measurements plays a crucial role in evaluating fetal growth impairment.

OBJECTIVE

This study aimed to investigate perinatal outcomes associated with discordant pulsatility indices of umbilical arteries in fetuses with growth restriction.

STUDY DESIGN

In this retrospective cohort study, all singleton pregnancies were included if their estimated fetal weight and/or abdominal circumference fell below the 10th percentile for gestational age (2017-2022). Eligible cases included singleton pregnancies with concurrent sampling of both umbilical arteries within 14 days of birth at the ultrasound evaluation closest to delivery. The exclusion criteria included births before 22 weeks of gestation, evidence of absent or reverse end-diastolic flow in either umbilical artery, and known fetal genetic or structural anomalies. The study compared cases with discordant umbilical artery pulsatility index values (defined as 1 umbilical artery pulsatility index at ≤95th percentile and the other umbilical artery pulsatility index at >95th percentile for gestational age) to pregnancies where both umbilical artery pulsatility indices had normal pulsatility index values and those with both umbilical arteries displaying abnormal pulsatility index values. The primary outcome assessed was the occurrence of composite adverse neonatal outcomes. Multivariable logistic regressions were performed, adjusting for relevant covariates.

RESULTS

The study encompassed 1014 patients, including 194 patients (19.1%) with discordant umbilical artery pulsatility index values among those who had both umbilical arteries sampled close to delivery, 671 patients (66.2%) with both umbilical arteries having normal pulsatility index values, and 149 patients (14.7%) with both umbilical arteries exhibiting abnormal values. Pregnancies with discordant umbilical artery pulsatility index values displayed compromised sonographic parameters compared with those with both umbilical arteries showing normal pulsatility index values. Similarly, the number of abnormal umbilical artery pulsatility index values was associated with adverse perinatal outcomes in a dose-response manner. Cases with 1 abnormal (discordant) umbilical artery pulsatility index value showed favorable sonographic parameters and perinatal outcomes compared with cases with both abnormal umbilical artery pulsatility index values, and cases with both abnormal umbilical artery pulsatility index values showed worse sonographic parameters and perinatal outcomes compared with cases with discordant UA PI values. Multivariate analysis revealed that discordant umbilical artery pulsatility indices were significantly and independently associated with composite adverse perinatal outcomes, with an adjusted odds ratio of 1.75 (95% confidence interval, 1.24-2.47; P = .002).

CONCLUSION

Evaluating the resistance indices of both umbilical arteries may provide useful data and assist in assessing adverse perinatal outcomes among fetuses with growth restriction.

Population adjusted-indirect comparisons in health technology assessment: A methodological systematic review

In health technology assessment (HTA), population-adjusted indirect comparisons (PAICs) are increasingly considered to adjust for the difference in the target population between studies. We aim to assess the conduct and reporting of PAICs in recent HTA practice, by performing, a methodological systematic review of studies implementing PAICs from PubMed, EMBASE Classic, Embase/Ovid Medline All, and Cochrane databases from January 1, 2010 to Feb 13, 2023. Four independent researchers screened the titles, abstracts, and full-texts of the identified records, then extracted data on methodological and reporting characteristics of 106 eligible articles. Most PAIC analyses (96.9%, n = 157) were conducted by (or received funding from) pharmaceutical companies. Prior to adjustment, 44.5% of analyses (n = 72) (partially) aligned the eligibility criteria of different studies to enhance the similarity of their target populations. In 37.0% of analyses (n = 60), the clinical and methodological heterogeneity across studies were extensively assessed. In 9.3% of analyses (n = 15), the quality (or bias) of individual studies was evaluated. Among 18 analyses using methods that required an outcome model specification, results of the model fitting procedure were adequately reported in three analyses (16.7%). These findings suggest that the conduct and reporting of PAICs are remarkably heterogeneous and suboptimal in current practice. More recommendations and guidelines on PAICs are thus warranted to enhance the quality of these analyses in the future.

Th17 / Treg ratio: A prospective study in a group of pregnant women with preeclampsia and fetal growth restriction

INTRODUCTION

During pregnancy, the maternal immune system is challenged to tolerate a semi-allogenic fetus. A proinflammatory profile has been linked to adverse pregnancy outcomes and poor placental development. In this study, the authors evaluated the number of circulating Tregs and Th17 cells in a group of patients diagnosed with preeclampsia(PE) and fetal growth restriction(FGR).

METHODS

Prospective longitudinal observational study where peripheral blood lymphocyte subsets were analyzed in a cohort of pregnant patients with PE, FGR, and a control group of healthy pregnant women.

RESULTS

The diagnosis of PE was associated with a significative higher number of circulating Th17 cells and a significative relative reduction in the Treg cell count. This proinflammatory profile was also expressed in the evolution of the Th17/ CD4+CD25highFOXP3+ Treg ratio. In the FGR group, the Th17 cell count was significantly higher during the third trimester of pregnancy. This proinflammatory profile was also expressed in the evolution of the Th17/ CD4+CD25highFOXP3+ Treg ratio. When we compare the immunological profiles of patients with PE and FGR we observed a higher number of proinflammatory Th17 cells and a significative lower number of Treg cells in PE patients. This is particularly expressed in the differences found between the Th17/ CD4+CD25highFOXP3+ Treg ratios of these two groups. Discussion/Conclusion Our data showed a that a proinflammatory profile and a relative excess of Th17 cells was associated with the diagnosis of PE and FGR. A more exuberant systemic proinflammatory profile present in the PE patients is absent in patients with FGR without preeclampsia.

Malaria Infections and Placental Blood Flow: A Doppler Ultrasound Study From a Preconception Cohort in Benin

Background

Malaria in pregnancy (MiP) has been associated with fetal growth restriction, the underlying pathogenic mechanisms of which remain poorly understood. Malaria in pregnancy is suspected to induce abnormalities in placental vascularization, leading to impaired placental development. Our study evaluated MIP's effect on uterine artery (UtA) and umbilical artery (UA) blood flow.

Methods

The analysis included 253 Beninese women followed throughout pregnancy and screened monthly for submicroscopic and microscopic malaria. Uterine artery Doppler measurement was performed once between 21 and 25 weeks' gestation (wg), and UA Doppler measurement was performed 1-3 times from 28 wg. Linear and logistic regression models were used to assess the effect of malaria infections on UtA Doppler indicators (pulsatility index and presence of a notch), whereas a logistic mixed model was used to assess the association between malaria infections and abnormal UA Doppler (defined as Z-score ≥2 standard deviation or absent/reversed UA end-diastolic flow).

Results

Primigravidae represented 7.5% of the study population; 42.3% of women had at least 1 microscopic infection during pregnancy, and 29.6% had at least 1 submicroscopic infection (and no microscopic infection). Both microscopic and submicroscopic infections before Doppler measurement were associated with the presence of a notch (adjusted odds ratio [aOR] 4.5, 95% confidence interval [CI] = 1.2-16.3 and aOR 3.3, 95% CI = .9-11.9, respectively). No associations were found between malaria before the Doppler measurement and abnormal UA Doppler.

Conclusions

Malaria infections in the first half of pregnancy impair placental blood flow. This highlights the need to prevent malaria from the very beginning of pregnancy.

Management of late-onset fetal growth restriction: pragmatic approach

OBJECTIVES

There is limited prospective evidence to guide the management of late-onset fetal growth restriction (FGR) and its differentiation from small-for-gestational age. The aim of this study was to assess prospectively a novel protocol in which ultrasound criteria were used to classify women with suspected late FGR into two groups: those at low risk, who were managed expectantly until the anticipated date of delivery, and those at high risk, who were delivered soon after 37 weeks of gestation. We also compared the outcome of this prospective cohort with that of a historical cohort of women presenting similarly with suspected late FGR, in order to evaluate the impact of the new protocol.

METHODS

This was a prospective study of women with a non-anomalous singleton pregnancy at ≥ 32 weeks' gestation attending a tertiary hospital in London, UK, between February 2018 and September 2019, with estimated fetal weight (EFW) ≤ 10th centile, or EFW > 10th centile in addition to a decrease in fetal abdominal circumference of ≥ 50 centiles compared with a previous scan, umbilical artery Doppler pulsatility index > 95th centile or cerebroplacental ratio < 5th centile. Women were classified as low or high risk based on ultrasound and Doppler criteria. Women in the low-risk group were delivered by 41 weeks of gestation, unless they subsequently met high-risk criteria, whereas women in the high-risk group (EFW < 3rd centile, umbilical artery Doppler pulsatility index > 95th centile or EFW between 3rd and 10th centiles (inclusive) with abdominal circumference drop or abnormal Dopplers) were delivered at or soon after 37 weeks. The primary outcome was adverse neonatal outcome and included hypothermia, hypoglycemia, neonatal unit admission, jaundice requiring treatment, suspected infection, feeding difficulties, 1-min Apgar score < 7, hospital readmission and any severe adverse neonatal outcome (perinatal death, resuscitation using inotropes or mechanical ventilation, 5-min Apgar score < 7, metabolic acidosis, sepsis, and cerebral, cardiac or respiratory morbidity). Secondary outcomes were adverse maternal outcome (operative delivery for abnormal fetal heart rate) and severe adverse neonatal outcome. Women managed according to the new protocol were compared with a historical cohort of 323 women delivered prior to the implementation of the new protocol, for whom management was guided by individual clinician expertise.

RESULTS

Over 18 months, 321 women were recruited to the prospective cohort, of whom 156 were classified as low risk and 165 were high risk. Adverse neonatal outcome was significantly less common in the low-risk compared with the high-risk group (45% vs 58%; adjusted odds ratio (aOR), 0.6 (95% CI, 0.4-0.9); P = 0.022). There was no significant difference in the rate of adverse maternal outcome (18% vs 24%; aOR, 0.7 (95% CI, 0.4-1.2); P = 0.142) or severe adverse neonatal outcome (3.8% vs 8.5%; aOR, 0.5 (95% CI, 0.2-1.3); P = 0.153) between the low- and high-risk groups. Compared with women in the historical cohort classified retrospectively as low risk, low-risk women managed under the new protocol had a lower rate of adverse neonatal outcome (45% vs 58%; aOR, 0.6 (95% CI, 0.4-0.9); P = 0.026).

CONCLUSIONS

Appropriate risk stratification to guide management of late FGR was associated with a reduced rate of adverse neonatal outcome in low-risk pregnancies. In clinical practice, a policy of expectantly managing women with a low-risk late-onset FGR pregnancy at term could improve neonatal and long-term development. Randomized controlled trials are needed to assess the effect of an evidence-based conservative management protocol for late FGR on perinatal morbidity and mortality and long-term neurodevelopment. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Fetal growth restriction and stillbirth: Biomarkers for identifying at risk fetuses

Fetal growth restriction (FGR) is a major cause of stillbirth, prematurity and impaired neurodevelopment. Its etiology is multifactorial, but many cases are related to impaired placental development and dysfunction, with reduced nutrient and oxygen supply. The fetus has a remarkable ability to respond to hypoxic challenges and mounts protective adaptations to match growth to reduced nutrient availability. However, with progressive placental dysfunction, chronic hypoxia may progress to a level where fetus can no longer adapt, or there may be superimposed acute hypoxic events. Improving detection and effective monitoring of progression is critical for the management of complicated pregnancies to balance the risk of worsening fetal oxygen deprivation in utero, against the consequences of iatrogenic preterm birth. Current surveillance modalities include frequent fetal Doppler ultrasound, and fetal heart rate monitoring. However, nearly half of FGR cases are not detected in utero, and conventional surveillance does not prevent a high proportion of stillbirths. We review diagnostic challenges and limitations in current screening and monitoring practices and discuss potential ways to better identify FGR, and, critically, to identify the “tipping point” when a chronically hypoxic fetus is at risk of progressive acidosis and stillbirth.

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.

Diagnosis and Monitoring of White Coat Hypertension in Pregnancy: an ISSHP Consensus Delphi Procedure

BACKGROUND

There is no accepted definition or standardized monitoring for white coat hypertension in pregnancy. This Delphi procedure aimed to reach consensus on out-of-office blood pressure (BP) monitoring, and white coat hypertension diagnostic criteria and monitoring.

METHOD

Relevant international experts completed three rounds of a modified Delphi questionnaire. For each item, the predefined cutoff for group consensus was ≥70% agreement, with 60% to 70% considered to warrant reconsideration at the subsequent round, and <60% considered insufficient to warrant consideration.

RESULTS

Of 230 experts, 137 completed the first round and 114 (114/137, 83.2%) completed all three. For out-of-office BP monitoring, there was consensus that home BP monitoring (HBPM) should be chosen; instructions given, pairs of BP values taken, opportunity given for women to qualify values they do not regard as valid, and BP considered evaluated when ≥25% of values are above a cutoff. For HBPM, BP should be taken at least 2 to 3 d/wk, at minimum in the morning; however, many factors may affect frequency and timing. Experts endorsed a clinic BP <140/90 mm Hg as normal. While not reaching consensus, most agreed that HBPM values should be lower than clinic BP. Among those, HBPM <135/85 mm Hg was considered normal. There was consensus that white coat hypertension warrants: HBPM at least 1 d/wk before 20 weeks, 2 to 3 d/wk after 20 weeks or if persistent hypertension develops, and symptom monitoring (ie, headache, visual symptoms, and right upper quadrant/epigastric pain).

CONCLUSIONS

Consensus-based diagnostic criteria and monitoring strategies should inform clinical care and research, to facilitate evaluation of out-of-office BP monitoring on pregnancy outcomes.

Abnormal Fetal Growth: Small for Gestational Age, Fetal Growth Restriction, Large for Gestational Age: Definitions and Epidemiology

Abnormal fetal growth (growth restriction and overgrowth) is associated with perinatal morbidity, mortality, and lifelong risks to health. To describe abnormal growth, "small for gestational age" and "large for gestational age" are commonly used terms. However, both are statistical definitions of fetal size below or above a certain threshold related to a reference population, rather than referring to an abnormal condition. Fetuses can be constitutionally small or large and thus healthy, whereas fetuses with seemingly normal size can be growth restricted or overgrown. Although golden standards to detect abnormal growth are lacking, understanding of both pathologic conditions has improved significantly.

Reduced Placental CD24 in Preterm Preeclampsia Is an Indicator for a Failure of Immune Tolerance

INTRODUCTION

CD24 is a mucin-like glycoprotein expressed at the surface of hematopoietic and tumor cells and was recently shown to be expressed in the first trimester placenta. As it was postulated as an immune suppressor, CD24 may contribute to maternal immune tolerance to the growing fetus. Preeclampsia (PE), a major pregnancy complication, is linked to reduced immune tolerance. Here, we explored the expression of CD24 in PE placenta in preterm and term cases.

METHODS

Placentas were derived from first and early second trimester social terminations (N = 43), and third trimester normal term delivery (N = 67), preterm PE (N = 18), and preterm delivery (PTD) (N = 6). CD24 expression was determined by quantitative polymerase chain reaction (qPCR) and Western blotting. A smaller cohort included 3-5 subjects each of term and early PE, and term and preterm delivery controls analyzed by immunohistochemistry.

RESULTS

A higher expression (2.27-fold) of CD24 mRNA was determined in the normal term delivery compared to first and early second trimester cases. The mRNA of preterm PE cases was only higher by 1.31-fold compared to first and early second trimester, while in the age-matched PTD group had a fold increase of 5.72, four times higher compared to preterm PE. The delta cycle threshold (ΔCt) of CD24 mRNA expression in the preterm PE group was inversely correlated with gestational age (r = 0.737) and fetal size (r = 0.623), while correlation of any other group with these parameters was negligible. Western blot analysis revealed that the presence of CD24 protein in placental lysate of preterm PE was significantly reduced compared to term delivery controls (p = 0.026). In immunohistochemistry, there was a reduction of CD24 staining in villous trophoblast in preterm PE cases compared to gestational age-matched PTD cases (p = 0.042). Staining of PE cases at term was approximately twice higher compared to preterm PE cases (p = 0.025) but not different from normal term delivery controls.

CONCLUSION

While higher CD24 mRNA expression levels were determined for normal term delivery compared to earlier pregnancy stages, this expression level was found to be lower in preterm PE cases, and could be said to be linked to reduced immune tolerance in preeclampsia.

Maternal Serum Inhibin-A Augments the Value of Maternal Serum PlGF and of sFlt-1/PlGF Ratio in the Prediction of Preeclampsia and/or FGR Near Delivery—A Secondary Analysis

Objective: We previously provided evidence to confirm that maternal serum levels of soluble Fms-like tyrosine kinase-1 (sFlt-1), placental growth factor (PlGF), and their ratio are useful tools to direct the management of preeclampsia (PE), fetal growth restriction (FGR), and PE+FGR near delivery. In this secondary analysis, we further examine the potential additive value of maternal serum Inhibin-A, which is a hormone marker of the transforming growth factor family, to the accuracy provided by maternal serum PlGF and sFlt-1. Methods: We conducted a secondary analysis where we extracted the data of a cohort of 125 pregnant women enrolled near delivery at the clinics of the University Medical Center of Ljubljana, Slovenia. The dataset included 31 cases of PE, 16 of FGR, 42 of PE+FGR, 15 preterm delivery (PTD), and 21 unaffected controls with delivery of a healthy baby at term. Cases delivered before 34 weeks’ gestation included 10 of PE, 12 of FGR, 28 of PE+FGR, and 6 of PTD. In addition to the recorded demographic characteristics and medical history and the maternal serum levels of PlGF and sFlt-1/PlGF ratio, which were previously published, we evaluated the added value of maternal serum Inhibin-A. The predictive accuracy of each biomarker, their ratios, and combinations were estimated from areas under the curve (AUC) of receiver operating characteristics (ROC) curves, Box and Whisker plots, and by multiple regression. We estimated accuracy by the continuous marker model and a cutoff model. Results: In this study, we combined Inhibin-A with PlGF or with the sFlt-1/PlGF ratio and showed a 10–20% increase in AUCs and 15–45% increase in the detection rate, at 10% false positive rate, of PE, and a lower, but significant, increase for PE+FGR and FGR in all cases but not for FGR in early cases delivered < 34 weeks. The use of a cutoff model was adequate, although a bit higher accuracy was obtained from the continuous model. The highest correlation was found for PlGF with all three complications. Conclusion: In this secondary analysis, we have found that maternal serum Inhibin-A improves the accuracy of predicting PE and PE+FGR provided by maternal serum angiogenic markers alone, bringing the results to a diagnostic level; thus, it could be considered for directing clinical management. Inhibin-A had smaller or no added value for the accuracy of predicting FGR alone, mainly of early cases delivered <34 weeks.

Pro- and Anti-Angiogenic Markers as Clinical Tools for Suspected Preeclampsia with and without FGR near Delivery—A Secondary Analysis

Objective—the objective of this study was to assess the accuracy of placental growth factor (PlGF), soluble Fms-like Tyrosine Kinase 1 (sFlt-1), and endoglin (sEng) in the diagnosis of suspected preeclampsia (PE) with and without fetal growth restriction (FGR) near delivery. Methods—this is a secondary analysis of a dataset of 125 pregnant women presenting at the high risk pregnancy clinic with suspected PE, FGR or PE + FGR in the University Medical Center of Slovenia. The dataset included 31 PE cases, 16 FGR cases, 42 PE + FGR cases, 15 cases who developed with unrelated complications before 37 weeks (wks) (PTD), and 21 unaffected controls who delivered a healthy baby at term. We also analyzed a sub-group of women who delivered early (<34 wks) including 10 PE, 12 FGR, 28 PE + FGR, and six PTD. Clinical management adhered to hospital guidelines. Marker levels were extracted from the dataset and were used to develop Receiver Operating Characteristic (ROC) curves and to calculate the area under the curve (AUC), the detection rates (DRs), and the false positive rates (FPRs). Previously published marker cutoffs for yes/no admission to hospital wards were extracted from the literature. Negative and positive predictive values (NPVs and PPVs) were evaluated for their value in determining whether hospital admission was required. Non-parametric tests were applied for statistical analysis; p < 0.05 was considered significant. Results—near delivery, all the pro-and anti-angiogenic markers provided diagnostic (ROC = 1.00) accuracy for the early (<34 wks) group of FGR. Diagnostic or near diagnostic (ROC = 0.95) accuracy was achieved by all marker for early PE + FGR but lower accuracy was achieved for early PE. For all cases, all markers, especially PlGF reached diagnostic or near diagnostic accuracy for FGR and PE + FGR. At this accuracy level, they can contribute to the clinical management of FGR, and PE + FGR. All the markers were less accurate for all PE cases. The use of published cutoffs was adequate for clinical management of FGR, whether early or for all cases, using an NPV > 90%. For PE + FGR, the PPV value approached 100%, especially for early cases, and can thus be implemented in clinical management. Neither NPV nor PPV were high enough for managing all cases of PE. There was no added value in measuring the PlGF/(sFlt-1 + sEng) ratio. Conclusion—This is the first study on a Slovenian population. It shows that near-delivery angiogenic biomarkers tests may be useful for confirming the diseases in cases where there is a diagnostic doubt. However, the clinical use of the biomarkers needs to be weighed against resources available and degree of certainty of the diagnosis made with and without them for managing suspected FGR and PE + FGR requiring delivery <34 wks, where they are very accurate, and furthermore in the management of all cases of FGR and FGR+PE. The markers were less accurate for the clinical diagnosis of PE.

A Core Outcome Set and minimum reporting set for intervention studies in growth restriction in the NEwbOrN: the COSNEON study

BACKGROUND

Different interventions and treatments are available for growth-restricted newborns to improve neonatal and long-term outcomes. Lack of outcome standardization across trials of feeding interventions limits pooled analysis of intervention effects. This study aimed to develop a core outcome set (COS) and minimum reporting set (MRS) for this research field.

METHODS

A scoping search identified relevant outcomes and baseline characteristics. These outcomes were presented to two stakeholder groups (lay experience and professional experts) in three rounds of online Delphi surveys. The professional experts were involved in the development of the MRS. All items were rated for their importance on a 5-point Likert scale and re-rated in subsequent rounds after presentation of the results at the group level. During a face-to-face consensus meeting the final COS and MRS were determined.

RESULTS

Forty-seven of 53 experts (89%) who completed the first round completed all three survey rounds. After the consensus meeting, consensus was reached on 19 outcomes and 17 baseline characteristics.

CONCLUSIONS

A COS and MRS for feeding interventions in the newborn after growth restriction were developed. Use of these sets will promote uniform reporting of study characteristics and improve data synthesis and meta-analysis of multiple studies.

IMPACT

Both a COS and MRS for growth restriction in the newborn were developed. This study provides the first international combined health-care professional and patient consensus on outcomes and baseline characteristics for intervention and treatment studies in growth-restricted newborns. The use of COS and MRS results in the development of more uniform study protocols, thereby facilitating data synthesis/meta-analysis of multiple studies aiming to optimize treatment and interventions in growth restriction in the newborn.

Identification of the optimal growth chart and threshold for the prediction of antepartum stillbirth

PURPOSE

To evaluate the effect of the choice growth chart and threshold used to define small for gestational age (SGA) on the predictive value of SGA for placenta-related or unexplained antepartum stillbirth.

METHODS

A retrospective cohort study of all women with a singleton pregnancy who gave birth > 24 week gestation in a single center (2000-2016). The exposure of interest was SGA, defined as birth weight < 10th or < 25th centile according to three fetal growth charts (Hadlock et al., Radiology 181:129-133, 1991; intergrowth-21st (IG21), WHO 2017, and a Canadian birthweight-based reference-Kramer et al., Pediatrics 108:E35, 2001). The outcome of interest was antepartum stillbirth due to placental dysfunction or unknown etiology. Cases of stillbirth attributed to other specific etiologies were excluded.

RESULTS

A total of 49,458 women were included in the cohort. There were 103 (0.21%) cases of stillbirth due to placental dysfunction or unknown etiology. For cases in the early stillbirth cluster (≤ 30 weeks), the detection rate was high and was similar for the three ultrasound-based fetal growth charts of Hadlock, IG21, and WHO (range 83.3-87.0%). In contrast, the detection rate of SGA for cases in the late stillbirth cluster (> 30 weeks) was low, being highest for WHO and Hadlock (36.7% and 34.7%, respectively), and lowest for IG21 (18.4%). Using a threshold of the 25th centile increased the detection rate for stillbirth by approximately 15-20% compared with that achieved by the 10th centile cutoff.

CONCLUSION

At > 30 week gestation, the Hadlock or WHO fetal growth charts provided the best balance between detection rate and false positive rate for stillbirth.

Validation of Delphi procedure consensus criteria for defining fetal growth restriction

OBJECTIVE

Recently, a Delphi procedure was used to establish new criteria for defining fetal growth restriction (FGR). These criteria require clinical validation. We sought to validate the Delphi consensus criteria by comparing their performance with that of our current definition (estimated fetal weight (EFW) < 10^th percentile) in predicting adverse neonatal outcome (ANO).

METHODS

This was a secondary analysis of data from a prospective cohort study of women referred for fetal growth assessment between 26 and 36 weeks' gestation. The current standard definition of FGR used in our clinical practice is EFW < 10^th percentile using Hadlock's fetal growth standard. The Delphi consensus criteria for FGR include either a very small fetus (abdominal circumference (AC) or EFW < 3^rd percentile) or a small fetus (AC or EFW < 10^th percentile) with additional abnormal Doppler findings or a decrease in AC or EFW by two quartiles or more. The primary outcome was the prediction of a composite of ANO including one or more of: admission to the neonatal intensive care unit, cord pH < 7.1, 5-min Apgar score < 7, respiratory distress syndrome, intraventricular hemorrhage, neonatal seizures or neonatal death. The discriminatory capacities of the two definitions of FGR for composite ANO and delivery of a small-for-gestational-age (SGA) neonate, defined as birth weight < 10^th percentile, were compared using area under the receiver-operating-characteristics curve (AUC). The sensitivity, specificity and predictive values of the methods were also compared.

RESULTS

Of 1055 pregnancies included in the study, composite ANO occurred in 139 (13.2%). There were only two cases of early FGR (before 32 weeks); therefore, the study focused on late FGR. Our current FGR diagnostic criterion of EFW < 10^th percentile was not associated significantly with composite ANO (relative risk (RR), 1.1 (95% CI, 0.6-1.8)), while the Delphi FGR criteria were (RR, 2.0 (95% CI, 1.2-3.3)). Our current definition of FGR showed higher discriminatory ability in the prediction of a SGA neonate (AUC, 0.69 (95% CI, 0.65-0.73)) than did the Delphi definition (AUC, 0.64 (95% CI, 0.60-0.67)) (P = 0.001). The AUCs of both definitions were poor for the prediction of composite ANO, despite slightly improved performance using the Delphi consensus definition of FGR (AUC, 0.53 (95% CI, 0.50-0.55)) compared with that of our current definition (AUC, 0.50 (95% CI, 0.48-0.53)) (P = 0.02).

CONCLUSION

The newly postulated criteria for defining FGR based on a Delphi procedure detects fewer cases of neonatal SGA than does our current definition of EFW < 10^th percentile, but is associated with a slight improvement in predicting ANO. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

International gestational age-specific centiles for umbilical artery Doppler indices: a longitudinal prospective cohort study of the INTERGROWTH-21st Project

BACKGROUND

Reference values for umbilical artery Doppler indices are used clinically to assess fetal well-being. However, many studies that have produced reference charts have important methodologic limitations, and these result in significant heterogeneity of reported reference ranges.

OBJECTIVES

To produce international gestational age-specific centiles for umbilical artery Doppler indices based on longitudinal data and the same rigorous methodology used in the original Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project.

STUDY DESIGN

In Phase II of the INTERGROWTH-21st Project (the INTERBIO-21st Study), we prospectively continued enrolling pregnant women according to the same protocol from 3 of the original populations in Pelotas (Brazil), Nairobi (Kenya), and Oxford (United Kingdom) that had participated in the Fetal Growth Longitudinal Study. Women with a singleton pregnancy were recruited at <14 weeks' gestation, confirmed by ultrasound measurement of crown-rump length, and then underwent standardized ultrasound every 5±1 weeks until delivery. From 22 weeks of gestation umbilical artery indices (pulsatility index, resistance index, and systolic/diastolic ratio) were measured in a blinded fashion, using identical equipment and a rigorously standardized protocol. Newborn size at birth was assessed using the international INTERGROWTH-21st Standards, and infants had detailed assessment of growth, nutrition, morbidity, and motor development at 1 and 2 years of age. The appropriateness of pooling data from the 3 study sites was assessed using variance component analysis and standardized site differences. Umbilical artery indices were modeled as functions of the gestational age using an exponential, normal distribution with second-degree fractional polynomial smoothing; goodness of fit for the overall models was assessed.

RESULTS

Of the women enrolled at the 3 sites, 1629 were eligible for this study; 431 (27%) met the entry criteria for the construction of normative centiles, similar to the proportion seen in the original fetal growth longitudinal study. They contributed a total of 1243 Doppler measures to the analysis; 74% had 3 measures or more. The healthy low-risk status of the population was confirmed by the low rates of preterm birth (4.9%) and preeclampsia (0.7%). There were no neonatal deaths and satisfactory growth, health, and motor development of the infants at 1 and 2 years of age were documented. Only a very small proportion (2.8%-6.5%) of the variance of Doppler indices was due to between-site differences; in addition, standardized site difference estimates were marginally outside this threshold in only 1 of 27 comparisons, and this supported the decision to pool data from the 3 study sites. All 3 Doppler indices decreased with advancing gestational age. The 3rd, 5th 10th, 50th, 90th, 95th, and 97th centiles according to gestational age for each of the 3 indices are provided, as well as equations to allow calculation of any value as a centile and z scores. The mean pulsatility index according to gestational age = 1.02944 + 77.7456*(gestational age)-2 - 0.000004455*gestational age3.

CONCLUSION

We present here international gestational age-specific normative centiles for umbilical artery Doppler indices produced by studying healthy, low-risk pregnant women living in environments with minimal constraints on fetal growth. The centiles complement the existing INTERGROWTH-21st Standards for assessment of fetal well-being.

A Core Outcome Set for the prevention and treatment of fetal GROwth restriction: deVeloping Endpoints: the COSGROVE study

BACKGROUND

Fetal growth restriction refers to a fetus that does not reach its genetically predetermined growth potential. It is well-recognized that growth-restricted fetuses are at increased risk of both short- and long-term adverse outcomes. Systematic evaluation of the evidence from clinical trials of fetal growth restriction is often difficult because of variation in the outcomes that are measured and reported. The development of core outcome sets for fetal growth restriction studies would enable future trials to measure similar meaningful outcomes.

OBJECTIVE

The purpose of this study was to develop core outcome sets for trials of prevention or treatment of fetal growth restriction.

STUDY DESIGN

This was a Delphi consensus study. A comprehensive literature review was conducted to identify outcomes that were reported in studies of prevention or treatment of fetal growth restriction. All outcomes were presented for prioritization to key stakeholders (135 healthcare providers, 68 researchers/academics, and 35 members of the public) in 3 rounds of online Delphi surveys. A priori consensus criteria were used to reach agreement on the final outcomes for inclusion in the core outcome set at a face-to-face meeting with 5 healthcare providers, 5 researchers/academics, and 6 maternity service users.

RESULTS

In total, 22 outcomes were included in the final core outcome set. These outcomes were grouped under 4 domains: maternal (n=4), fetal (n=1), neonatal (n=12), and childhood (n=5).

CONCLUSION

The Core Outcome Set for the prevention and treatment of fetal GROwth restriction: deVeloping Endpoints study identified a large number of potentially relevant outcomes and then reached consensus on those factors that, as a minimum, should be measured and reported in all future trials of prevention or treatment of fetal growth restriction. This will enable future trials to measure similar meaningful outcomes and to ensure that findings from different studies can be compared and combined.

Development of a Core Outcome Set and Minimum Reporting Set for intervention studies in growth restriction in the NEwbOrN (COSNEON): study protocol for a Delphi study

Background

Growth restriction in the newborn (GRN) can predispose to severe complications including hypoglycemia, sepsis, and necrotizing enterocolitis. Different interventions and treatments, such as feeding strategies, for GRN have specific benefits and risks. Comparing results from studies investigating intervention studies in GRN is challenging due to the use of different baseline and study characteristics and differences in reported study outcomes. In order to be able to compare study results and to allow pooling of data, uniform reporting of study characteristics (minimum reporting set [MRS]) and outcomes (core outcome set [COS]) are needed. We aim to develop both an MRS and a COS for interventional and treatment studies in GRN.

Methods/design

The MRS and COS will be developed according to Delphi methodology. First, a scoping literature search will be performed to identify study characteristics and outcomes in research focused on interventions/treatments in the GRN. An international group of stakeholders, including experts (clinicians working with GRN, and researchers who focus on GRN) and lay experts ([future] parents of babies with GRN), will be questioned to rate the importance of the study characteristics and outcomes in three rounds. After three rounds there will be two consensus meetings: a face-to-face meeting and an electronic meeting. During the consensus meetings multiple representatives of stakeholder groups will reach agreement upon which study characteristics and outcomes will be included into the COS and MRS. The second electronic consensus meeting will be used to test if an electronic meeting is as effective as a face-to-face meeting.

Discussion

In our opinion a COS alone is not sufficient to compare and aggregate trial data. Hence, to ensure optimum comparison we also will develop an MRS. Interventions in GRN infants are often complicated by coexisting preterm birth. A COS already has been developed for preterm birth. The majority of GRN infants are born at term, however, and we therefore chose to develop a separate COS for interventions in GRN, which can be combined (with expected overlap) in intervention studies enrolling preterm GRN babies.

Trial registration

Not applicable. This study is registered in the Core Outcome Measures for Effectiveness (COMET) database. Registered on 30 June 2017.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3588-9) contains supplementary material, which is available to authorized users.