Poor effectiveness of antenatal detection of fetal growth restriction and consequences for obstetric management and neonatal outcomes: a F rench national study

Prediction of preterm birth in growth-restricted and appropriate-for-gestational-age infants using maternal PlGF and the sFlt-1/PlGF ratio-A prospective study

OBJECTIVE

To assess the utility of placental growth factor (PlGF) levels and the soluble fms-like tyrosine kinase-1/placental growth factor (sFlt-1/PlGF) ratio to predict preterm birth (PTB) for infants with fetal growth restriction (FGR) and those appropriate for gestational age (AGA).

DESIGN

Prospective, observational cohort study.

SETTING

Tertiary maternity hospital in Australia.

POPULATION

There were 320 singleton pregnancies: 141 (44.1%) AGA, 83 (25.9%) early FGR (<32+0 weeks) and 109 (30.0%) late FGR (≥32+0 weeks).

METHODS

Maternal serum PlGF and sFlt-1/PlGF ratio were measured at 4-weekly intervals from recruitment to delivery. Low maternal PlGF levels and elevated sFlt-1/PlGF ratio were defined as <100 ng/L and >5.78 if <28 weeks and >38 if ≥28 weeks respectively. Cox proportional hazards models were used. The analysis period was defined as the time from the first measurement of PlGF and sFlt-1/PlGF ratio to the time of birth or censoring.

MAIN OUTCOME MEASURES

The primary study outcome was overall PTB. The relative risks (RR) of birth within 1, 2 and 3 weeks and for medically indicated and spontaneous PTB were also ascertained.

RESULTS

The early FGR cohort had lower median PlGF levels (54 versus 229 ng/L, p < 0.001) and higher median sFlt-1 levels (2774 ng/L versus 2096 ng/L, p < 0.001) and sFlt-1/PlGF ratio higher (35 versus 10, p < 0.001). Both PlGF <100 ng/L and elevated sFlt-1/PlGF ratio were strongly predictive for PTB as well as PTB within 1, 2 and 3 weeks of diagnosis. For both FGR and AGA groups, PlGF <100 ng/L or raised sFlt-1/PlGF ratio were strongly associated with increased risk for medically indicated PTB. The highest RR was seen in the FGR cohort when PlGF was <100 ng/L (RR 35.20, 95% CI 11.48-175.46).

CONCLUSIONS

Low maternal PlGF levels and elevated sFlt-1/PlGF ratio are potentially useful to predict PTB in both FGR and AGA pregnancies.

Neonatal Outcomes among Fetuses with an Abdominal Circumference <3rd %ile and Estimated Fetal Weight 3rd to 9th %ile Compared to Fetuses with an EFW <3rd %ile

OBJECTIVE

Fetal growth restriction (FGR) is defined as an estimated fetal weight (EFW) or abdominal circumference (AC) <10th percentile (%ile) for gestational age (GA). An EFW <3rd %ile for GA is considered severe FGR (sFGR). It remains unknown if fetuses with isolated AC <3rd %ile should be considered sFGR. Our primary objective was to assess composite neonatal outcomes in fetuses with an AC <3rd %ile and overall EFW 3rd to 9th %ile compared with those with an EFW <3rd %ile.

STUDY DESIGN

This retrospective cohort study was undertaken at a tertiary academic center from January 2016 to December 2021. Inclusion criteria were singleton fetuses with an EFW <3rd %ile (Group 1) or AC <3rd %ile with EFW 3rd to 9th %ile (Group 2) at 28 weeks' gestation or greater. Exclusion criteria were multiple gestations, presence of a major fetal anomaly, resolution of FGR, genetic syndrome, or infection. Composite neonatal outcome was defined by any of the following: neonatal intensive care unit admission >48 hours, necrotizing enterocolitis, sepsis, respiratory distress syndrome, mechanical ventilation, retinopathy of prematurity, seizures, intraventricular hemorrhage, stillbirth, or death before discharge. Small for gestational age (SGA) was defined as birth weight <10th %ile for GA.

RESULTS

A total of 743 patients fulfilled our study criteria, with 489 in Group 1 and 254 in Group 2. The composite neonatal outcome occurred in 281 (57.5%) neonates in Group 1 and 53 (20.9%) in Group 2 (p < 0.01). The rates of SGA at birth were 94.9 and 75.6% for Group 1 and Group 2, respectively (OR 5.99, 95% confidence interval 3.65-9.82).

CONCLUSION

Although AC <3rd %ile with EFW 3rd to 9th %ile is associated with a lower frequency of SGA and neonatal morbidity than EFW <3 %ile, fetuses with AC <3 %ile still exhibited moderate rates of these adverse perinatal outcomes. Consideration should be given to inclusion of an AC <3rd %ile with EFW 3rd to 9th %ile as a criterion for sFGR. However, prospective studies comparing delivery at 37 versus 38 to 39 weeks' gestation are needed to ensure improved outcomes before widespread adaptation in clinical practice.

KEY POINTS

· The composite neonatal outcome occurred in 57.5% of fetuses with an overall EFW <3rd %ile and 20.9% of fetuses with an AC <3rd %ile but EFW 3rd to 9th %ile.. · Both groups demonstrated a high positive predictive value for SGA birth weight.. · Consideration should be given to inclusion of an AC <3rd %ile as a criterion for sFGR..

3D Single Vessel Fractional Moving Blood Volume (3D-svFMBV): Fully Automated Tissue Perfusion Estimation Using Ultrasound

Power Doppler ultrasound (PD-US) is the ideal modality to assess tissue perfusion as it is cheap, patient-friendly and does not require ionizing radiation. However, meaningful inter-patient comparison only occurs if differences in tissue-attenuation are corrected for. This can be done by standardizing the PD-US signal to a blood vessel assumed to have 100% vascularity. The original method to do this is called fractional moving blood volume (FMBV). We describe a novel, fully-automated method combining image processing, numerical modelling, and deep learning to estimate three-dimensional single vessel fractional moving blood volume (3D-svFMBV). We map the PD signals to a characteristic intensity profile within a single large vessel to define the standardization value at the high shear vessel margins. This removes the need for mathematical correction for background signal which can introduce error. The 3D-svFMBV was first tested on synthetic images generated using the characteristics of uterine artery and physiological ultrasound noise levels, demonstrating prediction of standardization value close to the theoretical ideal. Clinical utility was explored using 143 first-trimester placental ultrasound volumes. More biologically plausible perfusion estimates were obtained, showing improved prediction of pre-eclampsia compared with those generated with the semi-automated original 3D-FMBV technique. The proposed 3D-svFMBV method overcomes the limitations of the original technique to provide accurate and robust placental perfusion estimation. This not only has the potential to provide an early pregnancy screening tool but may also be used to assess perfusion of different organs and tumors.

Comparative analysis of quality scores images between second- and third-trimester ultrasound scan

OBJECTIVES

To evaluate whether the quality scores validated for second-trimester ultrasound scan can be used for third-trimester ultrasound scan.

METHODS

Prospective multicenter ancillary study using data from the RECRET study. Nulliparous women, with no reported history, with second- and third-trimester ultrasound examinations performed by the same ultrasonographer and using the same ultrasound machine were recruited. The global score and the individual score of each ultrasound image were compared between second- and third-trimester ultrasound scan. The sample size was calculated for a non-inferiority (one-sided) paired Student t test.

RESULTS

103 women with 1606 anonymized ultrasound images were included. The median term at second- and third-trimester ultrasound scan was 22.2 weeks gestation (22.0-22.7) and 31.6 weeks gestation (30.7-34.7), respectively. The mean global score of ultrasound images was comparable between the second- and the third-trimester ultrasound examination (32.37 ± 2.62 versus 31.80 ± 3.27, p = 0.13). Means scores for each biometric parameters i.e. head circumference, abdominal circumference, and femur diaphysis length were comparable. The scores for the four-chamber view (5.11 ± 0.91 versus 5.36 ± 0.75, p = 0.02) and the spine (4.18 ± 1.17 versus 5.22 ± 1.02, p < 0.001) were significantly lower in the third trimester compared to the second trimester. The score for the kidney image was significantly higher for third trimester images compared to second trimester images (4.73 ± 0.51 versus 4.32 ± 0.67, p < 0.001.

CONCLUSIONS

Biometrics parameters quality scores images previously validated for the second trimester ultrasound scan can be also used for the third trimester scan. However, anatomical quality scores images performances may vary between the second and the third trimester scan.

Indicated vs universal third-trimester ultrasound examination in low-risk pregnancies: a pre-post-intervention study

BACKGROUND

In low-risk pregnancies, a third-trimester ultrasound examination is indicated if fundal height measurement and gestational age discrepancy are observed. Despite potential improvement in the detection of ultrasound abnormality, prior trials to date on universal third-trimester ultrasound examination in low-risk pregnancies, compared with indicated ultrasound examination, have not demonstrated improvement in neonatal or maternal adverse outcomes.

OBJECTIVE

The primary objective was to determine if universal third-trimester ultrasound examination in low-risk pregnancies could attenuate composite neonatal adverse outcomes. The secondary objectives were to compare changes in composite maternal adverse outcomes and detection of abnormalities of fetal growth (fetal growth restriction or large for gestational age) or amniotic fluid (oligohydramnios or polyhydramnios).

STUDY DESIGN

Our pre-post intervention study at 9 locations included low-risk pregnancies, those without indication for ultrasound examination in the third trimester. Compared with indicated ultrasound in the preimplementation period, in the postimplementation period, all patients were scheduled for ultrasound examination at 36.0-37.6 weeks. In both periods, clinicians intervened on the basis of abnormalities identified. Composite neonatal adverse outcomes included any of: Apgar score ≤5 at 5 minutes, cord pH <7.00, birth trauma (bone fracture or brachial plexus palsy), intubation for >24 hours, hypoxic-ischemic encephalopathy, seizure, sepsis (bacteremia proven with blood culture), meconium aspiration syndrome, intraventricular hemorrhage grade III or IV, periventricular leukomalacia, necrotizing enterocolitis, stillbirth after 36 weeks, or neonatal death within 28 days of birth. Composite maternal adverse outcomes included any of the following: chorioamnionitis, wound infection, estimated blood loss >1000 mL, blood transfusion, deep venous thrombus or pulmonary embolism, admission to intensive care unit, or death. Using Bayesian statistics, we calculated a sample size of 600 individuals in each arm to detect >75% probability of any reduction in primary outcome (80% power; 50% hypothesized risk reduction).

RESULTS

During the preintervention phase, 747 individuals were identified during the initial ultrasound examination, and among them, 568 (76.0%) met the inclusion criteria at 36.0-37.6 weeks; during the postintervention period, the corresponding numbers were 770 and 661 (85.8%). The rate of identified abnormalities of fetal growth or amniotic fluid increased from between the pre-post intervention period (7.1% vs 22.2%; P<.0001; number needed to diagnose, 7; 95% confidence interval, 5-9). The primary outcome occurred in 15 of 568 (2.6%) individuals in the preintervention and 12 of 661 (1.8%) in the postintervention group (83% probability of risk reduction; posterior relative risk, 0.69 [95% credible interval, 0.34-1.42]). The composite maternal adverse outcomes occurred in 8.6% in the preintervention and 6.5% in the postintervention group (90% probability of risk; posterior relative risk, 0.74 [95% credible interval, 0.49-1.15]). The number needed to treat to reduce composite neonatal adverse outcomes was 121 (95% confidence interval, 40-200). In addition, the number to reduce composite maternal adverse outcomes was 46 (95% confidence interval, 19-74), whereas the number to prevent cesarean delivery was 18 (95% confidence interval, 9-31).

CONCLUSION

Among low-risk pregnancies, compared with routine care with indicated ultrasound examination, implementation of a universal third-trimester ultrasound examination at 36.0-37.6 weeks attenuated composite neonatal and maternal adverse outcomes.

Long-term neurological outcomes of offspring misdiagnosed with fetal growth restriction

OBJECTIVE

Fetal growth restriction (FGR) is a major determinant of adverse short- and long-term perinatal outcomes. The current definition of FGR (estimated fetal weight measurement < 10th percentile) may lead, at times, to a false diagnosis of fetuses that are eventually born appropriate for gestational age (AGA). Our objective was to investigate the potential association between a misdiagnosis of antepartum fetal growth restriction and long-term neurological outcomes in offspring.

STUDY DESIGN

A population-based cohort analysis was performed including deliveries between the years 1991-2020 in a tertiary medical center. We compared neurological hospitalization during childhood among AGA infants falsely diagnosed as FGR versus AGA infants without a false FGR diagnosis. A Kaplan-Meier survival curve was used to assess cumulative morbidity and a Cox proportional hazards model was employed to control for confounders.

RESULTS

During the study period, 324,620 AGA infants met the inclusion criteria; 3249 of them were falsely classified as FGR. These offspring had higher rates of hospitalizations due to various neurological conditions, as compared to those without an FGR diagnosis (OR 1.431, 95% CI 1.278-1.608; P < 0.001). In addition, cumulative hospitalization incidence was elevated in the FGR group (log-rank P-value < 0.001). When controlling for confounders, a false FGR diagnosis remained independently associated with long-term neurological morbidities (adjusted HR 1.086, 95% CI 1.003-1.177, P = 0.043).

CONCLUSION

Misdiagnosis of FGR in the antepartum period is associated with an increased risk for offspring long-term neurological morbidities.

DLK1: A Novel Biomarker of Placental Insufficiency in Stillbirth and Live Birth

OBJECTIVE

Delta-like homolog 1 (DLK1) is a growth factor that is reduced in maternal sera in pregnancies with small for gestational age neonates. We sought to determine if DLK1 is associated with stillbirth (SB), with and without placental insufficiency.

STUDY DESIGN

A nested case-control study was performed using maternal sera from a multicenter case-control study of SB and live birth (LB). SB and LB were stratified as placental insufficiency cases (small for gestational age <5% or circulatory lesions on placental histopathology) or normal placenta controls (appropriate for gestational age and no circulatory lesions). Enzyme-linked immunosorbent assay (ELISA) was used to measure DLK1. The mean difference in DLK1 was compared on the log scale in an adjusted linear regression model with pairwise differences, stratified by term/preterm deliveries among DLK1 results in the quantifiable range. In exploratory analysis, geometric means were compared among all data and the proportion of "low DLK1" (less than the median value for gestational age) was compared between groups and modeled using linear and logistic regression, respectively.

RESULTS

Overall, 234 SB and 234 LB were analyzed; 246 DLK1 values were quantifiable within the standard curve. Pairwise comparisons of case and control DLK1 geometric means showed no significant differences between groups. In exploratory analysis of all data, adjusted analysis revealed a significant difference for the LB comparison only (SB: 71.9 vs. 99.1 pg/mL, p = 0.097; LB: 37.6 vs. 98.1 pg/mL, p = 0.005). In exploratory analysis of "low DLK1," there was a significant difference between the odds ratio of having "low DLK1" between preterm cases and controls for both SB and LB. There were no significant differences in geometric means nor "low DLK1" between SB and LB.

CONCLUSION

In exploratory analysis, more placental insufficiency cases in preterm SB and LB had "low DLK1." However, low DLK1 levels were not associated with SB.

KEY POINTS

· Maternally circulating DLK1 is correlated with placental insufficiency.. · Maternally circulating DLK1 is not correlated with SB.. · DLK1 is a promising marker for placental insufficiency..

Prediction of adverse neonatal adaptation in fetuses with severe fetal growth restriction after 34 weeks of gestation

OBJECTIVE

To establish a predictive model for adverse immediate neonatal adaptation (INA) in fetuses with suspected severe fetal growth restriction (FGR) after 34 gestational weeks (GW).

METHODS

We conducted a retrospective observational study at the University Hospitals of Strasbourg between 2000 and 2020, including 1,220 women with a singleton pregnancy and suspicion of severe FGR who delivered from 34 GW. The primary outcome (composite) was INA defined as Apgar 5-minute score <7, arterial pH <7.10, immediate transfer to pediatrics, or the need for resuscitation at birth. We developed and tested a logistic regression predictive model.

RESULTS

Adverse INA occurred in 316 deliveries. The model included six features available before labor: parity, gestational age, diabetes, middle cerebral artery Doppler, cerebral-placental inversion, onset of labor. The model could predict individual risk of adverse INA with confidence interval at 95 %. Taking an optimal cutoff threshold of 32 %, performances were: sensitivity 66 %; specificity 83 %; positive and negative predictive values 60 % and 87 % respectively, and area under the curve 78 %.

DISCUSSION

The predictive model showed good performances and a proof of concept that INA could be predicted with pre-labor characteristics, and needs to be investigated further.

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.

The influence of birthweight on mortality and severe neonatal morbidity in late preterm and term infants: an Australian cohort study

Background

The aim of this study was to detail incidence rates and relative risks for severe adverse perinatal outcomes by birthweight centile categories in a large Australian cohort of late preterm and term infants.

Methods

This was a retrospective cohort study of singleton infants (≥34+0 weeks gestation) between 2000 and 2018 in Queensland, Australia. Study outcomes were perinatal mortality, severe neurological morbidity, and other severe morbidity. Categorical outcomes were compared using Chi-squared tests. Continuous outcomes were compared using t-tests. Multinomial logistic regression investigated the effect of birthweight centile on study outcomes.

Findings

The final cohort comprised 991,042 infants. Perinatal mortality occurred in 1944 infants (0.19%). The incidence and risk of perinatal mortality increased as birthweight decreased, peaking for infants <1st centile (perinatal mortality rate 13.2/1000 births, adjusted Relative Risk Ratio (aRRR) of 12.96 (95% CI 10.14, 16.57) for stillbirth and aRRR 7.55 (95% CI 3.78, 15.08) for neonatal death). Severe neurological morbidity occurred in 7311 infants (0.74%), with the highest rate (19.6/1000 live births) in <1st centile cohort. There were 75,243 cases of severe morbidity (7.59% livebirths), with the peak incidence occurring in the <1st centile category (12.3% livebirths). The majority of adverse outcomes occurred in infants with birthweights between 10 and 90th centile. Almost 2 in 3 stillbirths, and approximately 3 in 4 cases of neonatal death, severe neurological morbidity or other severe morbidity occurred within this birthweight range.

Interpretation

Although the incidence and risk of perinatal mortality, severe neurological morbidity and severe morbidity increased at the extremes of birthweight centiles, the majority of these outcomes occurred in infants that were apparently "appropriately grown" (i.e., birthweight 10th-90th centile).

Funding

National Health and Medical Research Council, Mater Foundation, Royal Australian College of Obstetricians and Gynaecologists Women's Health Foundation - Norman Beischer Clinical Research Scholarship, Cerebral Palsy Alliance, University of Queensland Research Scholarship.

Placental T2* and BOLD effect in response to hyperoxia in normal and growth-restricted pregnancies: multicenter cohort study

OBJECTIVES

Blood-oxygen-level-dependent (BOLD) magnetic resonance imaging (MRI) facilitates the non-invasive in-vivo evaluation of placental oxygenation. The aims of this study were to identify and quantify a relative BOLD effect in response to hyperoxia in the human placenta and to compare it between pregnancies with and those without fetal growth restriction (FGR).

METHODS

This was a prospective multicenter study (NCT02238301) of 19 pregnancies with FGR (estimated fetal weight (EFW) on ultrasound < 5th centile) and 75 non-FGR pregnancies (controls) recruited at two centers in Paris, France. Using a 1.5-Tesla MRI system, the same multi-echo gradient-recalled echo (GRE) sequences were performed at both centers to obtain placental T2* values at baseline and in hyperoxic conditions. The relative BOLD effect was calculated according to the equation 100 × (hyperoxic T2* - baseline T2*)/baseline T2*. Baseline T2* values and relative BOLD effect were compared according to EFW (FGR vs non-FGR), presence/absence of Doppler anomalies and birth weight (small-for-gestational age (SGA) vs non-SGA).

RESULTS

We observed a relative BOLD effect in response to hyperoxia in the human placenta (median, 33.8% (interquartile range (IQR), 22.5-48.0%)). The relative BOLD effect did not differ significantly between pregnancies with and those without FGR (median, 34.4% (IQR, 24.1-48.5%) vs 33.7% (22.7-47.4%); P = 0.95). Baseline T2* Z-score adjusted for gestational age at MRI was significantly lower in FGR pregnancies compared with non-FGR pregnancies (median, -1.27 (IQR, -4.87 to -0.10) vs 0.33 (IQR, -0.81 to 1.02); P = 0.001). Baseline T2* Z-score was also significantly lower in those pregnancies that subsequently delivered a SGA neonate (n = 23) compared with those that delivered a non-SGA neonate (n = 62) (median, -0.75 (IQR, -3.48 to 0.29) vs 0.35 (IQR, -0.79 to 1.05); P = 0.01).

CONCLUSIONS

Our study confirms a BOLD effect in the human placenta and that baseline T2* values are significantly lower in pregnancies with FGR. Further studies are needed to evaluate whether such parameters may detect placental insufficiency before it has a clinical impact on fetal growth. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

[Prostaglandins or cervical balloon for the induction of labor for cervical ripening: A literature review]

OBJECTIVE

Induction of labor in France concerns one birth out of four with 70% of induction starting by cervical ripening, either with a pharmacological (prostaglandins) or a mechanical (balloon) method. This review aims to compare these two methods within current knowledge, using the PRISMA methodology.

METHODS

Trials comparing these two methods, published or unpublished up to July 2023, in French or English were searched for in the PubMed, Cochrane Library and ClinicalTrial.govs datasets. Fifty articles including 10,689 women were selected. The outcomes of interest were those from the Core Outcome Set for trails on Induction of Labour (COSIOL) list: mode of delivery, time from induction-to-birth, maternal and neonatal morbidity, and maternal satisfaction.

RESULT

No differences were observed between the two methods for the mode of delivery or neonatal and maternal morbidity. The time from induction-to-birth was longer for mechanical methods. Those were also associated with a greater need for oxytocin, less uterine hyperstimulation and less instrumental deliveries. Maternal satisfaction was assessed in only nine trials using various scales which made the interpretation of maternal satisfaction.

CONCLUSION

The efficacy of these two induction methods is similar for vaginal delivery, but it remains to be seen which one best meets women's satisfaction criteria.

Accuracy of Estimated Fetal Weight by Ultrasound Versus Leopold Maneuver

ABSTRACT

Estimated fetal weight (EFW) is frequently used for clinical decision-making in obstetrics. The goals of this study were to determine the accuracy of EFW assessments by Leopold and ultrasound and to investigate any associations with maternal characteristics. Postgraduate years 1 and 2 obstetrics and gynecology resident physicians from Harbor-UCLA Medical Center from 2014 to 2020 performed EFW assessments on 10 preterm (<37 weeks' gestational age) fetuses by ultrasound biometry and 10 full-term (≥37 weeks' gestational age) fetuses by ultrasound biometry and Leopold maneuver. Assessments were included if the patients delivered within 2 weeks of the assessments. One thousand six hundred ninety-seven EFW assessments on 1183 patients performed by 33 residents were analyzed; 72.6% of sonographic full-term EFWs, 69% of Leopold full-term EFWs, and 61.5% of sonographic preterm EFWs were within 10% of the neonatal birth weight (BW). The lowest estimation error in our study occurred when actual BW was 3600 to 3700 g. After adjusting for BW, residents were found to have lower accuracy when the mother had a higher body mass index (BMI) for full-term estimation methods (Leopold and ultrasound, β = 0.13 and 0.12, P = 0.001 and 0.002, respectively). Maternal BMI was not related to estimation error for preterm fetuses ( β = 0.01, P = 0.75). Clinical and sonographic EFW assessments performed by obstetrics and gynecology junior residents are within 10% of neonatal BW much of the time. In our cohort, they tended to overestimate EFWs of lower-BW infants and underestimate EFWs of higher-BW infants. Accuracy of full-term EFW assessments seems to decrease with increasing maternal BMI.

Screening for small for gestational age infants in early vs late third-trimester ultrasonography: a randomized trial

BACKGROUND

Recent studies have demonstrated that a routine third-trimester ultrasound scan may improve the detection of small for gestational age infants when compared with clinically indicated ultrasound scans but with no reported reduction in severe perinatal morbidity. Establishing the optimal gestational age for the third-trimester examination necessitates evaluation of the ability to detect small for gestational age infants and to predict maternal and perinatal outcomes. Intrauterine growth restriction most often corresponds with small for gestational age infants associated with pathologic growth patterns.

OBJECTIVE

This study aimed to assess the performance of routine early ultrasound scans vs late ultrasound scans during the third trimester of pregnancy to identify small for gestational age infants and fetuses with intrauterine growth restriction.

STUDY DESIGN

This was an open-label, randomized, parallel trial conducted in Upper Normandy, France, from 2012 to 2015. The study eligibility criteria were heathy, nulliparous women older than 18 years with gestational age determined using the crown-rump length at the first trimester routine scan and with no fetal malformation or suspected small for gestational age fetus at the routine second trimester scan. Pregnant women were randomly assigned to a third-trimester scan group at 31 weeks gestational age ±6 days (early ultrasound scan) or at 35 weeks gestational age ±6 days (late ultrasound scan). The primary outcome of this trial was the ability of a third trimester scan to predict small for gestational age infants (customized birth weight <10th percentile) and intrauterine growth restriction (customized birth weight

RESULTS

Results from 1853 women assigned to the early ultrasound scan group and 1848 women assigned to the late ultrasound scan group were analyzed. The sensitivity was found to be higher in the late ultrasound scan group than in the early ultrasound scan group, both for identifying small for gestational age infants (27%; 22%-32% vs 17%; 13%-22%; P=.004) and intrauterine growth restriction (44%; 35%-54% vs 18%; 11%-27%; P<.001). There was little difference in the specificity between the late ultrasound scan and early ultrasound scan groups in identifying cases of small for gestational age (97%; 96%-98% and 98%; 97%-99%, respectively; P=.04) and intrauterine growth restriction (96%; 95%-97% and 97%; 96%;-97%, respectively; P=.24). Overall, the maternal and neonatal outcomes were comparable between the early ultrasound scan and late ultrasound scan groups with the exception of additional (at least 1) ultrasound scans performed (25% in the early ultrasound scan group vs 19% in the late ultrasound scan group; P<.001). Rates of perinatal death (0.4% vs 0.8%; P=.12) and adverse perinatal outcomes (1.8% vs 2.7%; P=.08) were comparable between the early ultrasound scan and late ultrasound scan assigned groups, and the overall sensitivity to detect small for gestational age infants and intrauterine growth restriction, including in the last ultrasound scan performed before delivery, were also similar (30%; 25%-36% vs 26%; 21%-31%; P=.23; and 50%; 40%-60% vs 38%; 28%-48%; P=.07).

CONCLUSION

A late ultrasound scan performed in the third trimester increases the probability of detecting small for gestational age infants and intrauterine growth restriction with fewer additional scans reported than for the early ultrasound scan group. The overall perinatal outcome risk was comparable between the 2 groups. However, the overall sensitivity for detecting small for gestational age fetuses and intrauterine growth restriction, including in the last ultrasound scan performed before delivery, remains comparable between the late ultrasound scan and early ultrasound scan groups.

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Key Words

• intrauterine growth restriction
• perinatal mortality and morbidity
• screening
• small for gestational age
• ultrasonography

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MESH Headings

• Female
• Humans
• Pregnancy
• Birth Weight
• Fetal Growth Retardation/diagnostic imaging
• Fetal Growth Retardation/epidemiology
• Gestational Age
• Pregnancy Trimester, Third
• Ultrasonography, Prenatal/methods

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Affiliation(s)

Eric Verspyck Department of Obstetrics and Gynecology, Rouen University Hospital, Rouen, France (Drs Verspyck, Brasseur-Daudruy, Braund, and Benichou).
Caroline Thill Department of Biostatistics, Rouen University Hospital, Rouen, France (Dr Thill)
Anne Ego University Grenoble Alpes, CNRS, Public Health Department CHU Grenoble Alpes, Grenoble Institute of Engineering, TIMC-IMAG, 38000 Grenoble, France (Dr Ego); INSERM UMR 1153, Obstetrical, Perinatal and Pediatric Epidemiology Research Team (EPOPé), Center for Epidemiology and Statistics Sorbonne Paris Cité (CRESS), FHU PREMA, Paris Descartes University, Paris, France (Dr Ego)
Elise Machevin Department of Obstetrics and Gynecology, Evreux Hospital, Evreux, France (Dr Machevin)
Marie Brasseur-Daudruy Department of Obstetrics and Gynecology, Rouen University Hospital, Rouen, France (Drs Verspyck, Brasseur-Daudruy, Braund, and Benichou)
Valentine Ickowicz Department of Obstetrics and Gynecology, Belvedere Hospital, Mont Saint Aignan, France (Dr Ickowicz)
Caroline Blondel Department of Obstetrics and Gynecology, Mathilde Private Clinic, Rouen, France (Dr Blondel)
Sophie Degré Department of Obstetrics and Gynecology, Le Havre Hospital, Le Havre, France (Dr Degré)
Anne Lefebure Department of Obstetrics and Gynecology, Elbeuf Hospital, Elbeuf, France (Dr Lefebure)
Sophia Braund Department of Obstetrics and Gynecology, Rouen University Hospital, Rouen, France (Drs Verspyck, Brasseur-Daudruy, Braund, and Benichou)
Jacques Benichou Department of Obstetrics and Gynecology, Rouen University Hospital, Rouen, France (Drs Verspyck, Brasseur-Daudruy, Braund, and Benichou); Inserm U1018, University of Rouen and University Paris-Saclay, Rouen, France (Dr Benichou); Department of Biostatistics, Rouen University Hospital, Rouen, France (Dr Benichou)

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Value of placental virtual magnetic resonance elastography and intravoxel incoherent motion-based diffusion and perfusion in predicting adverse outcomes of small-for-gestational-age infants

OBJECTIVE

It is critical to early monitor and manage small-for-gestational age (SGA) infants with truly adverse outcomes not detected by conventional methods. We aimed to explore the value of diffusion-weighted imaging (DWI)-based virtual magnetic resonance elastography (vMRE) and intravoxel incoherent motion (IVIM)-based biexponential and stretched exponential parameters in predicting adverse outcomes of SGA infants.

METHODS

Twenty SGA infants with adverse outcomes and forty without adverse outcomes were included in this prospective study. One DWI-based vMRE parameter [the stiffness value (μdiff)], five IVIM-based parameters [true diffusion coefficient (D), pseudo-diffusion coefficient (D*), perfusion fraction (f), diffusion distribution coefficient (DDC), and diffusion heterogeneity index (Alpha)] and apparent diffusion coefficient (ADC) were calculated and compared between groups. The predictive efficiency was compared by the logistic regression analysis and receiver operating characteristic curve analysis. The relationship between the μdiff value with gestational age was also evaluated.

RESULTS

The placental μdiff value was remarkably higher, and the f, DDC, and ADC values were considerably lower in the SGA infants with adverse outcomes compared with those without adverse outcomes. The μdiff and f value were predictive risk factors for SGA infants with adverse outcomes. A combined predictive model (μdiff and f) improved the predictive efficacy. Moreover, there was no statistically significant correlation between the placental stiffness value and gestational age.

CONCLUSIONS

Functional MRI parameters to quantify placenta elastography and microcirculation in SGA patients. This might be a useful tool to assess placental function and a vital non-invasive supplement for predicting adverse outcomes of SGA infants.

CRITICAL RELEVANCE STATEMENT

This prospective study shows DWI-based virtual magnetic resonance elastography and intravoxel incoherent motion-based functional parameters to quantify placenta elastography and microcirculation in small-for-gestational-age patients, which could complement existing non-invasive methods for monitoring and predicting neonatal perinatal adverse outcome.

KEY POINTS

• vMRE is an emerging non-invasive imaging technique for evaluating placenta stiffness. • SGA infants with adverse outcome have stiffer placental elasticity and lower microcirculation. • Risk factors combination displayed better efficacy in predicting adverse outcomes of SGA.

Implication of third-trimester screening accuracy for small-for-gestational age and additive value of third-trimester growth-trajectory indicators in predicting severe adverse perinatal outcome in low-risk population: pragmatic secondary analysis of IRIS study

OBJECTIVES

To examine the implications of third-trimester small-for-gestational-age (SGA) screening accuracy on severe adverse perinatal outcome (SAPO) and obstetric intervention in a low-risk population. Furthermore, we aimed to explore the additive value of third-trimester sonographic growth-trajectory measurements in predicting SAPO and obstetric intervention.

METHODS

This was a secondary analysis of a Dutch national multicenter stepped-wedge-cluster randomized trial among 11 820 low-risk pregnant women. Using multilevel multivariable logistic regression analysis, we compared SAPO and obstetric interventions in SGA neonates with and without SGA suspected prenatally (true positives and false negatives) and non-SGA neonates with and without SGA suspected prenatally (false positives and true negatives). In a subsample (n = 7989), we analyzed the associations of abdominal circumference (AC) and estimated fetal weight (EFW) < 10th centile (p10) and third-trimester growth-trajectory indicators AC and EFW crossing > 20 and AC crossing > 50 centiles and the lowest decile of AC growth-velocity Z-scores (ACGV < 10%) with SAPO and obstetric interventions.

RESULTS

SGA infants, i.e. the true-positive and false-negative cases, had an increased risk of SAPO (adjusted odds ratio (aOR), 4.46 (95% CI, 2.28-8.75) and aOR 2.61 (95% CI, 1.74-3.89), respectively), and obstetric intervention (aOR for: induction of labor, 2.99 (95% CI, 2.15-4.17) and 1.38 (95% CI, 1.14-1.66); Cesarean section, 1.82 (95% CI, 1.25-2.66) and 1.27 (95% CI, 1.05-1.54); medically indicated preterm delivery, 2.67 (95% CI, 1.97-3.62) and 1.20 (95% CI, 1.03-1.40)). The false-positive cases did not differ from the true negatives for all outcomes, including obstetric intervention. Of the third-trimester growth-trajectory indicators, only ACGV < 10% was associated moderately with SAPO (aOR, 2.15 (95% CI, 1.17-3.97)), while AC and EFW crossing > 20 and AC crossing > 50 centiles were not. Both EFW < p10 alone (aOR, 1.95 (95% CI, 1.13-3.38)) and EFW < p10 combined with ACGV < 10% (aOR, 4.69 (95% CI, 1.99-11.07)) were associated with SAPO, and they performed equally well in predicting SAPO (area under the receiver-operating-characteristics curve, 0.71 (95% CI, 0.65-0.76) vs 0.72 (95% CI, 0.67-0.77), P = 0.51).

CONCLUSION

Neonates who had been suspected falsely of being SGA during pregnancy had no higher rates of obstetric intervention than did those without suspicion of SGA prenatally. Our results do not support that third-trimester low fetal growth velocity (ACGV < 10%) may be of additive value for the identification of fetuses at risk of SAPO in populations remaining at low risk throughout pregnancy. AC and EFW crossing > 20 and AC crossing > 50 centiles performed poorly in identifying abnormal fetal growth. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Influence of chest/head circumference ratio at birth on obstetric and neonatal outcomes: The Japan environment and children's study

OBJECTIVES

Some newborns that are not small-for-gestational-age (non-SGA, birthweight ≥10th percentile for a given gestational age) may have pathologic growth restrictions. This study examined the association of adverse obstetric and neonatal outcomes with chest/head circumference ratio at birth in non-SGA and SGA newborns.

METHODS

This study was a cross-sectional evaluation of data from a nationwide prospective birth cohort study, the Japan Environment and Children's Study. We analyzed 93 690 non-anomalous singletons born at 34-41 gestational weeks. We defined low, normal, and high chest/head circumference ratio as <10th percentile, 10th-90th percentile, and >90th percentile, respectively, according to the internally constructed chest/head circumference percentile chart. Modified Poisson regression was used to estimate adjusted prevalence ratios (aPR) for the outcomes studied.

RESULTS

Compared with non-SGA newborns with a normal ratio, those with a low ratio had an increased occurrence of low birthweight (1.75, 1.58-1.94 [aPR, 95% confidence interval]), cesarean delivery (1.34, 1.29-1.38), Apgar score <7 at 5 min (1.57, 1.14-2.17), respiratory complications (1.20, 1.04-1.39), and prolonged hospitalization (1.36, 1.30-1.42). In contrast, the high-ratio group had a lower rate of low birthweight (0.71, 0.59-0.86), cesarean delivery (0.82, 0.77-0.87), and prolonged hospitalization (0.83, 0.78-0.89). In SGA newborns, a low ratio was associated with increased aPRs for low birthweight, cesarean delivery, hypoglycemia, and prolonged hospitalization, whereas a high ratio showed no such association.

CONCLUSIONS

Findings indicate that the chest/head circumference ratio at birth influence obstetric and neonatal outcomes regardless of the birthweight status.

Prediction of Perinatal and Neurodevelopmental Outcomes in Newborns with a Birth Weight below the 3rd Percentile: Performance of Two International Curves - Prospective Cohort from a Brazilian City

OBJECTIVES

 To evaluate the performance of Intergrowth-21 st (INT) and Fetal Medicine Foundation (FMF) curves in predicting perinatal and neurodevelopmental outcomes in newborns weighing below the 3rd percentile.

METHODS

 Pregnant women with a single fetus aged less than 20 weeks from a general population in non-hospital health units were included. Their children were evaluated at birth and in the second or third years of life. Newborns (NB) had their weight percentiles calculated for both curves. Sensitivity, specificity, positive (PPV) and negative predictive value (NPV), and area under the ROC curve (ROC-AUC) for perinatal outcomes and neurodevelopmental delay were calculated using birth weight < 3rd percentile as the cutoff.

RESULTS

 A total of 967 children were evaluated. Gestational age at birth was 39.3 (±3.6) weeks and birth weight was 3,215.0 (±588.0) g. INT and FMF classified 19 (2.4%) and 49 (5.7%) newborns below the 3rd percentile, respectively. The prevalence of preterm birth, tracheal intubation >24 hours in the first three months of life, 5th minute Apgar <7, admission to a neonatal care unit (NICU admission), cesarean section rate, and the neurodevelopmental delay was 9.3%, 3.3%, 1.3%, 5.9%, 38.9%, and 7.3% respectively. In general, the 3rd percentile of both curves showed low sensitivity and PPV and high specificity and NPV. The 3rd percentile of FMF showed superior sensitivity for preterm birth, NICU admission, and cesarean section rate. INT was more specific for all outcomes and presented a higher PPV for the neurodevelopmental delay. However, except for a slight difference in the prediction of preterm birth in favor of INT, the ROC curves showed no differences in the prediction of perinatal and neurodevelopmental outcomes.

CONCLUSION

 Birth weight below the 3rd percentile according to INT or FMF alone was insufficient for a good diagnostic performance of perinatal and neurodevelopmental outcomes. The analyzes performed could not show that one curve is better than the other in our population. INT may have an advantage in resource contingency scenarios as it discriminates fewer NB below the 3rd percentile without increasing adverse outcomes.

[Review of the literature on intrauterine and birthweight charts]

OBJECTIVES

To describe the main intrauterine and birthweight charts and review the studies comparing their performance for the identification of infants at risk of adverse perinatal outcomes.

METHODS

We carried out a literature search using Medline and selected the charts most frequently cited in the literature, French charts and those recently published.

RESULTS

Current knowledge on the association between mortality and morbidity and growth anomalies (small and large for gestational age) mostly relies on the use of descriptive charts which describe the weight distribution in unselected populations. Prescriptive charts, which describe ideal growth in low risk populations, have been constructed more recently. Few studies have evaluated whether the thresholds used to identify infants at risk with descriptive charts (such as the 3^rd or the 10^th percentile) are applicable to prescriptive charts. There is a large variability in the percentage of fetuses or newborns identified as being at risk by each chart, with from 3 to 25% having with a weight under the 10^th percentile, regardless of whether descriptive or prescriptive charts are used. The sensitivity and specificity of antenatal screening for small or large for gestational age newborns depends on the chart used to derive estimated fetal weight percentiles.

CONCLUSION

There is marked variability between intrauterine growth charts that can influence the percentage of infants identified as having abnormal growth. These results show that before the adoption of a growth chart, it is essential to evaluate whether it adequately describes the population and its performance for identifying of infants at risk because of growth anomalies.

Intrauterine Growth Restriction-Prediction and Peripartum Data on Hospital Care

Background and Objectives: We aimed to prospectively obtain data on pregnancies complicated with intrauterine growth restriction (IUGR) in the Prenatal Diagnosis Unit of the Emergency County Hospital of Craiova. We collected the demographic data of mothers, the prenatal ultrasound (US) features, the intrapartum data, and the immediate postnatal data of newborns. We aimed to assess the detection rates of IUGR fetuses (the performance of the US in estimating the actual neonatal birth weight), to describe the prenatal care pattern in our unit, and to establish predictors for the number of total hospitalization days needed postnatally. Materials and Methods: Data were collected from cases diagnosed with IUGR undergoing prenatal care in our hospital. We compared the percentile of estimated fetal weight (EFW) using the Hadlock 4 technique with the percentile of weight at birth. We retrospectively performed a regression analysis to correlate the variables predicting the number of hospitalization days. Results: Data on 111 women were processed during the period of 1 September 2019-1 September 2022. We confirmed the significant differences in US features between early- (Eo) and late-onset (Lo) IUGR cases. The detection rates were higher if the EFW was lower, and Eo-IUGR was associated with a higher number of US scans. We obtained a mathematical formula for estimating the total number of hospitalization days needed postnatally. Conclusion: Early- and late-onset IUGR have different US features prenatally and different postnatal outcomes. If the US EFW percentile is lower, a prenatal diagnosis is more likely to be made, and a closer follow-up is offered in our hospital. The total number of hospitalization days may be predicted using intrapartum and immediate postnatal data in both groups, having the potential to optimize the final financial costs and to organize the neonatal department efficiently.

Characteristics associated with antenatally unidentified small-for-gestational-age fetuses: prospective cohort study nested within DESiGN randomized controlled trial

OBJECTIVE

To identify the clinical characteristics and patterns of ultrasound use amongst pregnancies with an antenatally unidentified small-for-gestational-age (SGA) fetus, compared with those in which SGA is identified, to understand how to design interventions that improve antenatal SGA identification.

METHODS

This was a prospective cohort study of singleton, non-anomalous SGA (birth weight < 10th centile) neonates born after 24 + 0 gestational weeks at 13 UK sites, recruited for the baseline period and control arm of the DESiGN trial. Pregnancy with antenatally unidentified SGA was defined if there was no scan or if the final scan showed estimated fetal weight (EFW) at the 10th centile or above. Identified SGA was defined if EFW was below the 10th centile at the last scan. Maternal and fetal sociodemographic and clinical characteristics were studied for associations with unidentified SGA using unadjusted and adjusted logistic regression models. Ultrasound parameters (gestational age at first growth scan, number and frequency of ultrasound scans) were described, stratified by presence of indication for serial ultrasound. Associations of unidentified SGA with absolute centile and percentage weight difference between the last scan and birth were also studied on unadjusted and adjusted logistic regression, according to time between the last scan and birth.

RESULTS

Of the 15 784 SGA babies included, SGA was not identified antenatally in 78.7% of cases. Of pregnancies with unidentified SGA, 47.1% had no recorded growth scan. Amongst 9410 pregnancies with complete data on key maternal comorbidities and antenatal complications, the risk of unidentified SGA was lower for women with any indication for serial scans (adjusted odds ratio (aOR), 0.56 (95% CI, 0.49-0.64)), for Asian compared with white women (aOR, 0.80 (95% CI, 0.69-0.93)) and for those with non-cephalic presentation at birth (aOR, 0.58 (95% CI, 0.46-0.73)). The risk of unidentified SGA was highest among women with a body mass index (BMI) of 25.0-29.9 kg/m2 (aOR, 1.15 (95% CI, 1.01-1.32)) and lowest in those with underweight BMI (aOR, 0.61 (95% CI, 0.48-0.76)) compared to women with BMI of 18.5-24.9 kg/m2 . Compared to women with identified SGA, those with unidentified SGA had fetuses of higher SGA birth-weight centile (adjusted odds for unidentified SGA increased by 1.21 (95% CI, 1.18-1.23) per one-centile increase between the 0th and 10th centiles). Duration between the last scan and birth increased with advancing gestation in pregnancies with unidentified SGA. SGA babies born within a week of the last growth scan had a mean difference between EFW and birth-weight centiles of 19.5 (SD, 13.8) centiles for the unidentified-SGA group and 0.2 (SD, 3.3) centiles for the identified-SGA group (adjusted mean difference between groups, 19.0 (95% CI, 17.8-20.1) centiles).

CONCLUSIONS

Unidentified SGA was more common amongst women without an indication for serial ultrasound, and in those with cephalic presentation at birth, BMI of 25.0-29.9 kg/m2 and less severe SGA. Ultrasound EFW was overestimated in women with unidentified SGA. This demonstrates the importance of improving the accuracy of SGA screening strategies in low-risk populations and continuing performance of ultrasound scans for term pregnancies. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Placental perfusion using intravoxel incoherent motion MRI combined with Doppler findings in differentiating between very low birth weight infants and small for gestational age infants

INTRODUCTION

Abnormalities in placental morphology and function can lead to small for gestational age infants (SGA) and very low birth weight infants (VLBWI). In this study, we explored the value of intravoxel incoherent motion (IVIM) histogram parameters, MRI morphological parameters, and Doppler findings of the placenta in differentiating between VLBWI and SGA.

METHODS

Thirty-three pregnant women who were diagnosed with SGA and met the inclusion criteria were enrolled in this retrospective study and divided into two groups: 22 with non-VLBWI and 11 with VLBWI. The IVIM histogram parameters (perfusion fraction (f), true diffusion coefficient (D), and pseudo-diffusion coefficient (D*)), MRI morphological parameters, and Doppler findings were compared between groups. The diagnostic efficiency was compared by receiver operating characteristic (ROC) curve analysis.

RESULTS

The D_mean, D_90th, D*_90th, f_max, and placental area of the VLBWI group were significantly lower than those of the non-VLBWI group (p < 0.05). The values of umbilical artery pulsatility index, resistance index (RI), and peak systolic velocity/end-diastolic velocity were significantly higher in the VLBWI group than in the non-VLBWI group (p < 0.05). D_90th, placental area, and umbilical artery RI had the highest areas under the curve (AUCs) of the ROC curves, at 0.787, 0.785, and 0.762, respectively. A combined predictive model (D_90th, placental area, and umbilical artery RI) improved the performance in differentiating between VLBWI and SGA compared with the single model (AUC = 0.942).

DISCUSSION

IVIM histogram (D_90th) and MRI morphological (placental area) parameters and a Doppler finding (umbilical artery RI) may be sensitive indicators for differentiating between VLBWI and SGA.

Comparative Diagnostic Performance of Estimated Fetal Weight and Isolated Abdominal Circumference for the Detection of Fetal Growth Restriction

OBJECTIVES

To describe the comparative incidence, detection of small-for-gestational age (SGA), and composite perinatal morbidity (CPM) associated with diagnostic criteria of fetal growth restriction (FGR) by estimated fetal weight (EFW) <10% with those with isolated abdominal circumference (AC) measurements <10%.

METHODS

We performed a retrospective cohort study of 1587 patients receiving prenatal care and delivery at our institution. We included all patients with ultrasounds and delivery outcomes available, and excluded terminations, second trimester losses, and pregnancies without ultrasounds. EFW was calculated from Hadlock and use of the Duryea centiles, and AC from Hadlock's reference curves. We determined SGA at birth and defined CPM as birthweight less than 3% or birthweight less than 10% with neonatal morbidity.

RESULTS

Of 1587 patients, 28 (1.8%) were classified as FGR by EFW <10%. Three of 12 patients with isolated AC <10% developed EFW <10% later in pregnancy (25%). The performance of each diagnostic criteria were comparable for the outcomes of SGA and CPM, with similar sensitivities, but with decreased specificity for SGA outcome, and an increased false positive rate for patients classified as FGR by isolated AC <10, with a tradeoff of decreased false negatives.

CONCLUSIONS

Broadening the diagnosis of FGR to include patients with isolated AC <10 did not significantly increase the detection of pregnancies at risk for SGA or CPM. Our conclusions may be limited by a lack of statistical power given a low frequency of SGA and CPM.

Combination of Fundal Height and Ultrasound to Predict Small for Gestational Age at Birth

OBJECTIVE

The objective of the study was to determine whether adding longitudinal measures of fundal height (FH) to the standard cross-sectional FH to trigger third trimester ultrasound estimated fetal weight (EFW) would improve small for gestational age (SGA) prediction.

STUDY DESIGN

We developed a longitudinal FH calculator in a secondary analysis of a prospective cohort study of 1,939 nonobese pregnant women who underwent serial FH evaluations at 12 U.S. clinical sites. We evaluated cross-sectional FH measurement ≤ -3 cm at visit 3 (mean: 32.0 ± 1.6 weeks) versus the addition of longitudinal FH up to and including visit 3 to trigger an ultrasound to diagnose SGA defined as birth weight <10th percentile. If the FH cut points were not met, the SGA screen was classified as negative. If FH cut points were met and EFW was <10th percentile, the SGA screen was considered positive. If EFW was ≥10th percentile, the SGA screen was also considered negative. Sensitivity, specificity, and positive predictive value (PPV) and negative predictive value (NPV) were computed.

RESULTS

In a comparison of methods, 5.8% of women were classified as at risk of SGA by both cross-sectional and longitudinal classification methods; cross-sectional FH identified an additional 4.0%, and longitudinal fundal height identified a separate, additional 4.5%.Using cross-sectional FH as an ultrasound trigger, EFW had a PPV and NPV for SGA of 69 and 92%, respectively. After adding longitudinal FH, PPV increased to 74%, whereas NPV of 92% remained unchanged; however, the number of women who underwent triggered EFW decreased from 9.7 to 5.7%.

CONCLUSION

An innovative approach for calculating longitudinal FH to the standard cross-sectional FH improved identification of SGA birth weight, while simultaneously reducing the number of triggered ultrasounds. As an essentially free-of-charge screening test, our novel method has potential to decrease costs as well as perinatal morbidity and mortality (through better prediction of SGA).

KEY POINTS

· We have developed an innovative calculator for fundal height trajectory.. · Longitudinal fundal height improves detection of SGA.. · As a low cost screening test, the fundal height calculator may decrease costs and morbidity through better prediction of SGA..

Impact of a Hybrid Model of Prenatal Care on the Diagnosis of Fetal Growth Restriction

OBJECTIVE

Fetal growth restriction (FGR) is associated with poor neonatal outcomes and stillbirth, and screening via fundal height or ultrasound is routinely performed. During the novel coronavirus disease 2019 (COVID-19) pandemic, we developed a hybrid model of prenatal care which decreased the frequency of in-person visits and incorporated telemedicine visits. We sought to determine if prenatal FGR diagnoses decreased with this hybrid model compared with routine prenatal care.

STUDY DESIGN

This was a retrospective cohort study of singleton nonanomalous neonates with birth weights <10th percentile at term. The "routine care" group was consisted of those who born between April and July 2019 with in-person prenatal care, and the "hybrid care" group was consisted of those who born between April and July 2020 with both in-person and telemedicine prenatal cares at a collaborative academic practice. The primary outcome was the rate of diagnosis of small for gestational age (SGA) as defined as infant birth weight <10th percentile without a prenatal diagnosis of FGR. The secondary outcome was timing of diagnosis of FGR.

RESULTS

Overall, 1,345 and 1,296 women gave birth in the routine and hybrid groups, respectively. The number of in-person prenatal care visits decreased from 15,024 in the routine period to 7,727 in the hybrid period; 3,265 telemedicine visits occurred during the hybrid period. The total number of prenatal patients remained relatively stable at 3,993 and 3,753 between periods. Third trimester ultrasounds decreased from 2,929 to 2,014 between periods. Birth weights <10 percentile occurred in 115 (8.6%) births during the routine period and 79 (6.1%) births during the hybrid period. Of 115, 44 (38.3%) cases were prenatally diagnosed with FGR in the routine versus 28 of 79 (35.4%) in the hybrid group (p = 0.76). Median gestational age at diagnosis did not vary between groups (36 vs. 37 weeks, p = 0.44).

CONCLUSION

A hybrid prenatal care model did not alter the detection of FGR. Future efforts should further explore the benefits of incorporating telemedicine into prenatal care.

KEY POINTS

· Telemedicine visits can provide comprehensive prenatal care.. · FGR was diagnosed equally with hybrid versus routine prenatal care.. · FGR diagnosis was not delayed with hybrid care..

Severity of small-for-gestational-age and morbidity and mortality among very preterm neonates

OBJECTIVE

Evaluate the association between small for gestational age (SGA) severity and morbidity and mortality in a contemporary, population of very preterm infants.

STUDY DESIGN

This secondary analysis of a California statewide database evaluated singleton infants born during 2008-2018 at 24-32 weeks' gestation, with a birthweight <15th percentile. We analyzed neonatal outcomes in relation to weight for gestational age (WGA) and symmetry of growth restriction.

RESULTS

An increase in WGA by one z-score was associated with decreased major morbidity or mortality risk (aRR 0.73, 95% CI 0.68-0.77) and other adverse outcomes. The association was maintained across gestational ages and did not differ by fetal growth restriction diagnosis. Symmetric growth restriction was not associated with neonatal outcomes after standardizing for gestational age at birth.

CONCLUSIONS

Increasing SGA severity had a significant impact on neonatal outcomes among very preterm infants.

Performance of a risk factor-based approach in the detection of small for gestational age neonates: A cohort study

BACKGROUND

Antenatal detection of fetal growth restriction allows the opportunity to increase surveillance and initiate intervention to prevent adverse outcomes. Detection of small for gestational age (SGA) fetuses with risk factor screening and selective ultrasonography is the standard of care in Australia, but evidence regarding performance is lacking.

AIMS

To evaluate the diagnostic performance of a risk factor-based screening approach in detection of SGA neonates.

MATERIALS AND METHODS

Retrospective cohort study conducted in a metropolitan maternity service, including all consecutive singleton deliveries over 20 weeks gestation from July 2016 to December 2017, and excluding terminations of pregnancy. An SGA neonate was defined by birthweight below the tenth percentile according to Australian reference ranges. Antenatally detected SGA cases were defined by estimated fetal weight or abdominal circumference below the tenth percentile for gestational age, or abnormal symphysio-fundal height. The diagnostic accuracy of the screening protocol was calculated using detection rates and false-positive rates.

RESULTS

There were 13 384 singleton pregnancies included. There were 1330 infants (10.0%) who were SGA at birth. Antenatal detection rate of SGA neonates was 39.6% (95% confidence interval (CI) 37.0-42.3%), with a false-positive rate of 10.2% (95% CI 9.6-10.7%). There were 10 266 pregnancies (77.0%) which had at least one risk factor for an SGA infant. Of these, 6650 (64.8%) underwent at least one fetal growth ultrasound after 24 weeks gestation.

CONCLUSIONS

Antenatal recognition of poor fetal growth is suboptimal using our current screening protocol. Three-quarters of pregnancies demonstrated risk factors for delivering an SGA infant, but growth ultrasonography may be underutilised.

Diagnosis of mid-second trimester fetal growth restriction and associated outcomes

OBJECTIVE

To evaluate maternal and neonatal outcomes of low-risk singleton pregnancies, without underlying maternal medical conditions or genetic and fetal anomalies associated with fetal growth restriction, that were diagnosed with fetal growth restriction (FGR) (EFW < 10th %) in the mid-second trimester (between 17 and 22 weeks and 6 days' gestation).

METHODS

A retrospective cohort study of all women who underwent a routine fetal anatomy ultrasound between 17 and 22 weeks and 6 days' gestation at a community-based academic hospital was performed to identify subjects with an EFW <10th%. Pregnancies with inadequate dating, multiple gestations, preexisting maternal vascular disease (chronic hypertension and pregestational diabetes), lethal fetal anomalies, and abnormal prenatal genetic screening were excluded. Descriptive statistics were computed to describe the study population. Subjects were stratified into two groups, estimated fetal weight (EFW) <5th% and EFW 5th-9th%. The primary outcome was a small for gestational age neonate (SGA) at delivery. Secondary outcomes included a composite adverse neonatal outcome, perinatal death, hypertensive disorders of pregnancy, medically indicated delivery, and mode of delivery. A comparison of the two groups, EFW <5th% and EFW 5th-9th %, was performed. Continuous variables were compared utilizing Wilcoxon Rank Sum tests and categorical variables were compared using Fisher's exact test or Chi-squared tests, and a dichotomous composite variable for adverse neonatal outcomes was also calculated.

RESULTS

In total, 3,868 unique patient records were screened. Thirty-two patient records (0.8% of the total screened records) were eligible for inclusion. The primary outcome, SGA at delivery, occurred in 13/32 (41%) of the subjects. The secondary outcomes of the composite neonatal morbidity occurred in 9/32 (28%), hypertensive disorders of pregnancy in 10/32 (31%), and medically indicated delivery at <28 weeks gestation in 7/32 (22%) of the subjects. When comparing EFW <5th% and EFW 5th-9th%, EFW <5th% had a larger percentage of SGA newborns (66% vs. 25%, p = .02, OR = 8.0 95% CI 1.5-42.5). EFW <5th% was also significantly associated with a greater composite adverse neonatal outcome when compared to EFW 5th-9th% (54% vs. 10%, p = .015). The subgroup with an EFW <5th% also had higher rates of adverse outcomes including preeclampsia (42% vs. 10%, p = .073), abnormal umbilical artery Doppler studies (50% vs. 15%, p = .049), and medically indicated delivery <28 weeks (42% vs. 10%, p = .07).

CONCLUSIONS

Early onset FGR is a associated with high rates of SGA at delivery, as well as several adverse maternal and neonatal outcomes which include hypertensive disorders of pregnancy, a greater composite neonatal morbidity, perinatal death, and medically indicated preterm delivery. EFW <5th% was associated with worse outcomes when compared to those with an EFW 5th%-9th%.

Effect of the Growth Assessment Protocol on the DEtection of Small for GestatioNal age fetus: process evaluation from the DESiGN cluster randomised trial

Background

Reducing the rate of stillbirth is an international priority. At least half of babies stillborn in high-income countries are small for gestational-age (SGA). The Growth Assessment Protocol (GAP), a complex antenatal intervention that aims to increase the rate of antenatal detection of SGA, was evaluated in the DESiGN type 2 hybrid effectiveness-implementation cluster randomised trial (n = 13 clusters). In this paper, we present the trial process evaluation.

Methods

A mixed-methods process evaluation was conducted. Clinical leads and frontline healthcare professionals were interviewed to inform understanding of context (implementing and standard care sites) and GAP implementation (implementing sites). Thematic analysis of interview text used the context and implementation of complex interventions framework to understand acceptability, feasibility, and the impact of context. A review of implementing cluster clinical guidelines, training and maternity records was conducted to assess fidelity, dose and reach.

Results

Interviews were conducted with 28 clinical leads and 27 frontline healthcare professionals across 11 sites. Staff at implementing sites generally found GAP to be acceptable but raised issues of feasibility, caused by conflicting demands on resource, and variable beliefs among clinical leaders regarding the intervention value. GAP was implemented with variable fidelity (concordance of local guidelines to GAP was high at two sites, moderate at two and low at one site), all sites achieved the target to train > 75% staff using face-to-face methods, but only one site trained > 75% staff using e-learning methods; a median of 84% (range 78–87%) of women were correctly risk stratified at the five implementing sites. Most sites achieved high scores for reach (median 94%, range 62–98% of women had a customised growth chart), but generally, low scores for dose (median 31%, range 8–53% of low-risk women and median 5%, range 0–17% of high-risk women) were monitored for SGA as recommended.

Conclusions

Implementation of GAP was generally acceptable to staff but with issues of feasibility that are likely to have contributed to variation in implementation strength. Leadership and resourcing are fundamental to effective implementation of clinical service changes, even when such changes are well aligned to policy mandated service-change priorities.

Trial registration

Primary registry and trial identifying number: ISRCTN 67698474. Registered 02/11/16. 10.1186/ISRCTN67698474.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13012-022-01228-1.

[Ante- and postnatal growth charts in France - guidelines for clinical practice from the Collège national des gynécologues et obstétriciens français (CNGOF) and from the Société française de néonatologie (SFN)]

OBJECTIVE

To recommend the most appropriate biometric charts for the detection of antenatal growth abnormalities and postnatal growth surveillance.

METHODS

Elaboration of specific questions and selection of experts by the organizing committee to answer these questions; analysis of the literature by experts and drafting conclusions by assigning a recommendation (strong or weak) and a quality of evidence (high, moderate, low, very low) and for each question; all these recommendations have been subject to multidisciplinary external review (obstetrician gynecologists, pediatricians). The objective for the reviewers was to verify the completeness of the literature review, to verify the levels of evidence established and the consistency and applicability of the resulting recommendations. The overall review of the literature, quality of evidence and recommendations were revised to take into consideration comments from external reviewers.

RESULTS

Antenatally, it is recommended to use all WHO fetal growth charts for EFW and common ultrasound biometric measurements (strong recommendation; low quality of evidence). Indeed, in comparison with other prescriptive curves and descriptive curves, the WHO prescriptive charts show better performance for the screening of SGA (Small for Gestational Age) and LGA (Large for Gestational Age) with adequate proportions of fetuses screened at extreme percentiles in the French population. It also has the advantages of having EFW charts by sex and biometric parameters obtained from the same perspective cohort of women screened by qualified sonographers who measured the biometric parameters according to international standards. Postnatally, it is recommended to use the updated Fenton charts for the assessment of birth measurements and for growth monitoring in preterm infants (strong recommendation; moderate quality of evidence) and for the assessment of birth measurements in term newborn (expert opinion).

CONCLUSION

It is recommended to use WHO fetal growth charts for antenatal growth monitoring and Fenton charts for the newborn.

Social inequalities in access to care at birth and neonatal mortality: an observational study

OBJECTIVE

To look at the association of socioeconomic status (SES) with the suitability of the maternity where children are born and its association with mortality.

DESIGN

Retrospective analysis of a prospective cohort constituted using hospital discharge databases.

SETTING

France POPULATION: Live births in 2012-2014 in maternity hospitals in mainland France followed until discharge from the hospital.

MAIN OUTCOME MEASURE

Unsuitability of the maternity to newborns' needs based on birth weight and gestational age, early transfers (within 24 hours of birth) and in-hospital mortality.

RESULTS

2 149 454 births were included, among which 155 646 (7.2%) were preterm. Preterm newborns with low SES were less frequently born in level III maternities than those with high SES. They had higher odds of being born in an unsuitable maternity (OR=1.174, 95% CI 1.114 to 1.238 in the lowest SES quintile compared with the highest), and no increase in the odds of an early transfer (OR=0.966, 95% CI 0.849 to 1.099 in the lowest SES quintile compared with the highest). Overall, newborns from the lowest SES quintile had a 40% increase in their odds of dying compared with the highest (OR=1.399, 95% CI 1.235 to 1.584).

CONCLUSIONS

Newborns with the lowest SES were less likely to be born in level III maternity hospitals compared with those with the highest SES, despite having higher prematurity rates. This was associated with a significantly higher mortality in newborns with the lowest SES. Strategies must be developed to increase health equity among mothers and newborns.

Derivation and assessment of a sex-specific fetal growth standard

PURPOSE

To derive a prescriptive sex-specific fetal growth standard and assess clinical management and outcomes according to sex-specific growth status.

MATERIALS AND METHODS

This was a secondary analysis of the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be (nuMoM2b), a prospective observational study of 10,038 nulliparas from eight U.S. centers who underwent ultrasounds at 14-20 and 22-29 weeks with outcomes ascertained after delivery. From these, we selected a nested cohort of lower risk participants (excluded those with chronic hypertension, pre-gestational diabetes, suspected aneuploidy, and preterm delivery) to derive a sex-specific equation for expected fetal growth using fetal weights by ultrasound and at birth. We compared the male-female discrepancy in the rate of weight <10th (small for gestational age [SGA]) and >90th (large for gestational age [LGA]) percentiles between the sex-specific and sex-neutral (Hadlock) standards. Using the full unselected cohort, we then assessed outcomes and clinical management according to sex-specific SGA and LGA status.

RESULTS

Overall, 7280 infants in the lower risk nested cohort were used to derive a sex-specific equation with fetal sex included as an equation intercept. The sex-neutral standard diagnosed SGA more often in female newborns (21% vs. 13%, p < .001) and LGA more often in male newborns (5% vs. 3%, p < .001). The sex-specific standard resolved these disparities (SGA: 9% vs. 10%, p = .23; LGA: 13% vs. 13%, p = .58). To approximate an unselected population, 1059 participants initially excluded for risk factors for abnormal growth were then included for our secondary objective (N = 8339). In this unselected cohort, 39% (95% CI 37.0-42.0%) of the 1498 newborns classified as SGA by the sex-neutral standard were reclassified as appropriate for gestational age (AGA) by the sex-specific standard. These reclassified newborns were more likely to be delivered for growth restriction despite having lower risk of morbidity (females) or comparable risk of morbidity (males) compared to newborns considered AGA by both methods. Of the 6485 newborns considered AGA by the sex-neutral standard, 737 (11.4%, 95% CI 10.6-12.2%) were reclassified as LGA by the sex-specific standard. These reclassified newborns had higher rates of cesarean for arrest of descent, cesarean for arrest of dilation, and shoulder dystocia than newborns considered AGA by both methods. None were reclassified from LGA to AGA by the sex-specific standard.

CONCLUSION

The Hadlock sex-neutral standard generates sex disparities in SGA and LGA at birth. Our sex-specific standard resolves these disparities and has the potential to improve accuracy of growth pathology risk stratification.

Reassurance from second trimester sonographic placental scan for pregnancies complicated by abnormal first trimester biomarkers

OBJECTIVE

Enhanced first trimester aneuploidy screening (eFTS) combines serum biomarkers and ultrasound. Abnormal biomarkers are associated with placental complications, such as fetal growth restriction (FGR). We aimed to evaluate whether a Midtrimester placental scan can provide reassurance regarding FGR in women with abnormal eFTS biomarkers.

METHODS

We conducted a retrospective cohort study of women who had eFTS and delivered at a single referral center. Women with abnormal biomarkers had a mid-trimester scan of the placenta (morphologic assessment, fetal biometry and uterine artery pulsatility index). We compared pregnancies with abnormal eFTS biomarkers and normal placental scans (study group) with those who had normal eFTS biomarkers (control group).

RESULTS

A total of 6,514 women were included, of whom 343 (5.3%) comprised the study group. Women in the study group had an increased risk of hypertensive disorders of pregnancy [(aOR)1.96(95%CI 1.21-3.16)], and preterm birth <37 weeks [aOR1.98(95%CI 1.33-2.95)] compared to the control group. Yet, their neonates were not at higher risk for FGR <3^rd, 5^th, or 10^th percentile [aOR1.16(95%CI 0.83-1.63), 1.14(95%CI 0.70-1.87), and 0.47(95%CI 0.17-1.27), respectively].

CONCLUSION

A normal second trimester placental scan provided reassurance regarding the risk of FGR in women at high risk based on abnormal eFTS biomarkers.

Translational insights into mechanisms and preventive strategies after renal injury in neonates

Adverse perinatal circumstances can cause acute kidney injury (AKI) and contribute to chronic kidney disease (CKD). Accumulating evidence indicate that a wide spectrum of perinatal conditions interferes with normal kidney development and ultimately leads to aberrant kidney structure and function later in life. The present review addresses the lack of mechanistic knowledge with regard to perinatal origins of CKD and provides a comprehensive overview of pre- and peri-natal insults, including genetic predisposition, suboptimal nutritional supply, obesity and maternal metabolic disorders as well as placental insufficiency leading to intrauterine growth restriction (IUGR), prematurity, infections, inflammatory processes, and the need for life-saving treatments (e.g. oxygen supplementation, mechanical ventilation, medications) in neonates. Finally, we discuss future preventive, therapeutic, and regenerative directions. In summary, this review highlights the perinatal vulnerability of the kidney and the early origins of increased susceptibility toward AKI and CKD during postnatal life. Promotion of kidney health and prevention of disease require the understanding of perinatal injury in order to optimize perinatal micro- and macro-environments and enable normal kidney development.

Low Maternal DLK1 Levels at 26 Weeks Is Associated With Small for Gestational Age at Birth

Detecting SGA (small for gestational age) during pregnancy improves the fetal and neonatal prognosis. To date, there is no valid antenatal biomarker of SGA used in clinical practice. Maternal circulating DLK1 (delta-like non-canonical notch ligand 1) levels have been shown to be significantly lower in pregnant women at 36 weeks of gestation (WG) who delivered a SGA newborn than in controls. Data in the literature are contradictory on the association between maternal circulating DLK1 levels and placental vascular dysfunction. The objective was to determine if maternal DLK1 levels in the second trimester of pregnancy are predictive of SGA, and to assess whether the measurement of DLK1 levels in maternal blood could be a means to distinguish SGA with placental vascular dysfunction from that due to other causes. We conducted a nested cased-control study within the EDEN mother-child cohort. 193 SGA (birth weight < 10^th percentile) and 370 mother-child control (birth weight between the 25^th and 75^th percentile) matched pairs were identified in the EDEN cohort. Maternal circulating DLK1 levels at 26 WG were significantly lower for children born SGA than for controls (27.7 ± 8.7 ng/mL vs 30.4 ± 10.6 ng/mL, p = 0.001). Maternal blood DLK1 levels in the first quartile (DLK1 < 22.85 ng/mL) were associated with an odds ratio for SGA of 1.98 [1.15 - 3.37]. DLK1 was less predictive of SGA than ultrasound, with an area under the curve of 0.578. Maternal circulating DLK1 levels were not significantly different in cases of SGA with signs of placental vascular dysfunction (n = 63, 27.1 ± 9.2 ng/mL) than in those without placental dysfunction (n = 129, 28.0 ± 8.5 ng/mL, p = 0.53). The level of circulating DLK1 is reduced in the second trimester of pregnancy in cases of SGA at birth, independently of signs of placental vascular dysfunction. However, DLK1 alone cannot predict the risk of SGA.

Third-trimester growth diversity in small fetuses classified as appropriate-for-gestational age or small-for-gestational age at birth

OBJECTIVE

We have shown previously that third-trimester growth in small fetuses (estimated fetal weight (EFW) < 10^th percentile) with birth weight (BW) < 10^th percentile is heterogeneous using individualized growth assessment (IGA). We aimed to test our hypothesis that individual growth patterns in small fetuses with BW > 10^th percentile are also variable but in different ways.

METHODS

This was a study of 191 cases with EFW < 10^th percentile and BW > 10^th percentile (appropriate-for-gestational-age (AGA) cohort), derived from the PORTO study. Composite size parameters were used to quantify growth pathology at individual third-trimester timepoints (individual composite prenatal growth assessment score (-icPGAS)). The fetal growth pathology score 1 (-FGPS1), calculated cumulatively from serial -icPGAS values, was used to characterize third-trimester growth patterns. Vascular-system evaluation included umbilical artery (UA) and middle cerebral artery (MCA) Doppler velocimetry. Outcome variables were birth age (preterm/term delivery) and BW (expressed as growth potential realization index for weight (GPRI_WT ) and percentile). The findings from the AGA cohort were compared with those from small fetuses (EFW < 10^th percentile) with BW < 10^th percentile (small-for-gestational-age (SGA) cohort).

RESULTS

The AGA cohort was found to have 134 fetuses (70%) with normal growth pattern and 57 (30%) with growth restriction based on IGA criteria. Seven growth-restriction -FGPS1 patterns were observed, including the previously defined progressive, late, adaptive and recovering types. The recovering type was the most common growth pattern in the AGA cohort (50.9%). About one-third of fetuses without any evidence of growth restriction had significant unexplained abnormalities in the UA (34%) and MCA (31%) and elevated mean GPRI_WT values (113 ± 12.5%). Comparison of the AGA and SGA cohorts indicated a significant difference in the distribution of -FGPS1 growth patterns (P = 0.0001). Compared with the SGA cohort, the AGA cohort had more fetuses with a normal growth pattern (70% vs 38%) and fewer cases with growth restriction (30% vs 62%). While the recovering type was the most common growth-restriction pattern in the AGA cohort (51%), the progressive type was the primary growth-restriction pattern in the SGA cohort (44%). No difference in the incidence of MCA or UA abnormality was found between the SGA and AGA cohorts when comparing subgroups of more than 10 fetuses.

CONCLUSIONS

Both normal-growth and growth-restriction patterns were observed in the AGA cohort using IGA, as seen previously in the SGA cohort. The seven types of growth restriction defined in the SGA cohort were also identified in AGA cases, but their distribution was significantly different. In one-third of cases without evidence of growth pathology in the AGA cohort, Doppler abnormalities in the UA and MCA were seen. This heterogeneity underscores the difficulty of accurate classification of fetal and neonatal growth status using conventional population-based methods. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Comparison of the performance of estimated fetal weight charts for the detection of small- and large-for-gestational age newborns with adverse outcomes: a French population-based study

OBJECTIVE

To compare the performance of estimated fetal weight (EFW) charts at the third trimester ultrasound for detecting small- and large-for-gestational age (SGA/LGA) newborns with adverse outcomes.

DESIGN

Nationally representative observational study.

SETTING

French maternity units in 2016.

POPULATION

9940 singleton live births with an ultrasound between 30 and 35 weeks of gestation.

METHODS

We compared three prescriptive charts (INTERGROWTH-21st, World Health Organization (WHO), Eunice Kennedy Shriver National Institute of Child Health and Human Development [NICHD]), four descriptive charts (Hadlock, Fetal Medicine Foundation, two French charts) and a French customised growth model (Epopé).

MAIN OUTCOME MEASURES

SGA and LGA (birthweights <10th and >90th percentiles) associated with adverse outcomes (low Apgar score, delivery-room resuscitation, neonatal unit admission).

RESULTS

2.1% and 1.1% of infants had SGA and LGA and adverse outcomes, respectively. The sensitivity and specificity for detecting these infants with an EFW <10th and >90th percentile varied from 29-65% and 84-96% for descriptive charts versus 27-60% and 83-96% for prescriptive charts. WHO and French charts were closest to the EFW distribution, yielding a balance between sensitivity and specificity for SGA and LGA births. INTERGROWTH-21st and Epopé had low sensitivity for SGA with high sensitivity for LGA. Areas under the receiving operator characteristics curve ranged from 0.62 to 0.74, showing low to moderate predictive ability, and diagnostic odds ratios varied from 7 to 16.

CONCLUSION

Marked differences in the performance of descriptive as well as prescriptive EFW charts highlight the importance of evaluating them for their ability to detect high-risk fetuses.

TWEETABLE ABSTRACT

Choice of growth chart strongly affected identification of high-risk fetuses at the third trimester ultrasound.

Deficient neural encoding of speech sounds in term neonates born after fetal growth restriction

Infants born after fetal growth restriction (FGR)-an obstetric condition defined as the failure to achieve the genetic growth potential-are prone to neurodevelopmental delays, with language being one of the major affected areas. Yet, while verbal comprehension and expressive language impairments have been observed in FGR infants, children and even adults, specific related impairments at birth, such as in the ability to encode the sounds of speech, necessary for language acquisition, remain to be disclosed. Here, we used the frequency-following response (FFR), a brain potential correlate of the neural phase locking to complex auditory stimuli, to explore the encoding of speech sounds in FGR neonates. Fifty-three neonates born with FGR and 48 controls born with weight adequate-for-gestational age (AGA) were recruited. The FFR was recorded to the consonant-vowel stimulus (/da/) during sleep and quantified as the spectral amplitude to the fundamental frequency of the syllable and its signal-to-noise ratio (SNR). The outcome was available in 45 AGA and 51 FGR neonates, yielding no differences for spectral amplitudes. However, SNR was strongly attenuated in the FGR group compared to the AGA group at the vowel region of the stimulus. These findings suggest that FGR population present a deficit in the neural pitch tracking of speech sounds already present at birth. Our results pave the way for future research on the potential clinical use of the FFR in this population, so that if confirmed, a disrupted FFR recorded at birth may help deriving FGR neonates at risk for postnatal follow-ups.

Unisex vs sex-specific estimated fetal weight charts for fetal growth monitoring: a population-based study

BACKGROUND

In contrast with birthweight or other growth charts, a feature of most intrauterine charts is that they are not differentiated by sex. Differences in weight by sex during pregnancy are considered to be relatively minor; however, small systematic differences may affect the sensitivity and specificity of screening for fetuses with growth restriction.

OBJECTIVE

To assess differences between unisex and sex-specific estimated fetal weight charts at the third-trimester ultrasound with regard to the sex ratio of fetuses detected with an estimated fetal weight <10th percentile and subsequent detection of small-for-gestational-age newborns with morbidity at birth.

STUDY DESIGN

The study included 9940 singleton live births from a French population-based study in 2016. Main outcomes were an estimated fetal weight <10th percentile at the routine third-trimester ultrasound between 30 and 35 weeks of gestation, and small for gestational age infants (birthweight <10th percentile) with neonatal morbidity (Apgar score <7 at 5 minutes and/or resuscitation in delivery room and/or admission to a neonatal unit). We used 2 charts with unisex and sex-specific options: the World Health Organization international standard chart and a customized chart for fetal sex based on Gardosi's gestation-related optimal weight model adapted to the French population (Epopé). Hadlock's unisex chart, commonly used in clinical care and research, was also included to provide an external reference. We compared the proportions of female and male fetuses with an estimated fetal weight <10th percentile and the sensitivity and specificity of such estimated fetal weight for predicting small-for-gestational-age newborns with morbidity when using unisex vs sex-specific charts, overall and by sex.

RESULTS

Among all singleton births, there were 51.6% males and 48.4% females. Males faced higher risks of being small-for-gestational-age with morbidity at birth (2.4% vs 1.8%; P=.031). Using the World Health Organization unisex chart, 6.9% of males and 9.9% of females had an estimated fetal weight <10th percentile vs 9.9% of males and 7.1% of females with the sex-specific chart; these proportions were 3.5% and 4.6% and 4.3% and 2.7%, respectively, for the Epopé. Proportions of estimated fetal weight <10th percentile using Hadlock's chart were slightly higher than those obtained using the unisex World Health Organization chart (7.5% of males and 10.6% of females), but the difference of about 3% was the same. The sensitivity of an estimated fetal weight <10th percentile for identifying small-for-gestational-age newborns with morbidity differed for males and females by type of chart; unisex charts detected more small-for-gestational-age females with morbidity and sex-specific charts detected more small-for-gestational-age males with morbidity, but the overall sensitivity was the same (49.1% for the World Health Organization chart and Hadlock's chart and 34.9% for the Epopé chart).

CONCLUSION

This study suggests that the use of sex-specific charts instead of unisex charts would reduce sex bias in intrauterine growth screening during the third trimester of pregnancy. Prospective studies are needed to assess the effects of using sex-specific charts rather than unisex charts on obstetrical management and outcomes.

Reduced Growth in Non-Small for Gestational Age Fetuses from 35 Weeks of Gestation to Birth and Perinatal Outcomes

OBJECTIVE

This study aimed to assess reduced fetal growth between 35 weeks of gestation and birth in non-small for gestational age fetuses associated with adverse perinatal outcomes (APOs).

MATERIAL AND METHOD

It is a retrospective cohort study of 9,164 non-small for gestational age fetuses estimated by ultrasound at 35 weeks. The difference between the birth weight percentile and the estimated percentile weight (EPW) at 35 weeks of gestation was calculated, and we studied the relationship of this difference with the appearance of APO. APOs were defined as cesarean or instrumental delivery rates for nonreassuring fetal status, 5-min Apgar score <7, arterial cord blood pH <7.10, and stillbirth. Fetuses that exhibited a percentile decrease between both moments were classified into 6 categories according to the amount of percentile decrease (0.01-10.0, 10.01-20.0, 20.01-30.0, 30.01-40.0, 40.01-50.0, and >50.0 percentiles). It was evaluated whether the appearance of APO was related to the amount of this percentile decrease. Relative risk (RR) was calculated in these subgroups to predict APOs in general and for each APO in particular. Receiver operating characteristic and area under curves (AUC) for the difference in the percentile was calculated, used as a continuous parameter in the entire study population.

RESULTS

The median gestational age at delivery in uncomplicated pregnancies was 40.0 (39.1-40.7) and in pregnancies with APOs 40.3 (49.4-41.0), p < 0.001. The prevalence of APOs was greater in the group of fetuses with a decrease in percentile (7.6%) compared to those with increased percentile (4.8%) (p < 0.001). The RR was 1.63 (95% CI: 1.365-1.944, p < 0.001). Although the differences were significant in all decreased percentile groups, RRs were significantly higher when decreased growth values were >40 points (RR: 2.036, 95% CI: 1.581-2.623, p < 0.001). The estimated value of the AUC for percentile decrease was 0.58 (0.56-0.61, p < 0.001).

CONCLUSION

Fetuses with a decrease in the EPW between the ultrasound at 35 weeks of gestation and birth have a higher risk of APOs, being double in fetuses with a decrease of >40 percentile points.

Detection and clinical outcome of small-for-gestational-age fetuses in the third trimester-A comparison between routine ultrasound examination and examination on indication

INTRODUCTION

Fetal growth restriction is a major risk factor for adverse perinatal outcome. As most of the growth-restricted fetuses are small for gestational age (SGA), an efficient antenatal screening method for SGA fetuses would have a major impact on perinatal health. The aim of this study was to compare the SGA prediction rate achieved with third-trimester routine ultrasound estimation of fetal weight (EFW) with that obtained using ultrasound examination on indication. The secondary aim was to evaluate the clinical outcome in relation to the SGA screening method.

MATERIAL AND METHODS

During 1995-2009, two perinatal centers in southern Sweden offered routine ultrasound examination at 32-34 gestational weeks to 99 265 women with singleton pregnancies. Of these, 59 452 (60%) underwent the ultrasound examination. The other population, comprising 24 868 pregnancies, was cared for in another three centers that used a risk-based method with ultrasound examinations on indication only. Of them, 5792 (23%) underwent ultrasound examination at 32-36 gestational weeks. The deviation in the EFW from the expected one was expressed as the EFW z-score, SGA EFW being defined as the EFW z-score less than -2. SGA prediction ability was assessed by receiver operating characteristic (ROC) curves. Crude and adjusted risk ratios were calculated for selected variables of perinatal outcome when comparing the populations.

RESULTS

The SGA prediction ability for routine ultrasound was high, area under the ROC curve was 0.90 (95% CI 0.89-0.91). For an EFW z-score of -1, the sensitivity was 67.3% and specificity was 90.5% among routinely screened pregnancies; corresponding numbers in the ultrasound on indication population were 34.3% and 96.6%. The screened population had a lower risk of preterm birth, birthweight z-score less than -3, and Apgar score less than 7 at 5 min with adjusted risk ratios 0.87 (95% CI 0.82-0.92), 0.75 (95% CI 0.61-0.92), and 0.77 (95% CI 0.68-0.87), respectively. No difference in perinatal mortality was detected. There were no differences in perinatal outcome between the two subcohorts of infants born SGA.

CONCLUSIONS

Third-trimester routine ultrasound improves the detection of SGA antenatally compared with ultrasound performed on indication, but no convincing improvement in perinatal outcome was identified.

The risk of recurrent small-for-gestational-age infants at term is dependent on the number of previously affected births

BACKGROUND

Small-for-gestational-age infants are at a substantially increased risk of perinatal complications, but the risk of recurrent small-for-gestational-age is not well known, particularly because there are many demographic and obstetrical factors that interact and modify this risk. We investigated the relationship between previous small-for-gestational-age births and the risk of recurrence at term in a large Australian cohort.

OBJECTIVE

We aimed to identify key demographic and obstetrical variables that influence the risk of recurrence of a small-for-gestational-age infant at term. The primary outcome measure was the odds of recurrence of small-for-gestational-age in subsequent pregnancies up to a maximum of 4 consecutive term births.

STUDY DESIGN

This was a retrospective analysis of women who had more than 1 consecutive nonanomalous, singleton, term live births between July 1997 and September 2018 at the Mater Mother's Hospital in Brisbane, Australia. Women with multiple pregnancy, preterm birth, or major congenital malformations were excluded. Small-for-gestational-age was defined as birthweight at the <10th centile. We calculated the odds of recurrence depending on the number of previous small-for-gestational-age infants and if only the preceding infant was small-for-gestational-age. The study population was dichotomized into small-for-gestational-age and non-small-for-gestational-age for each consecutive pregnancy. Univariate analyses compared baseline demographic and obstetrical characteristics followed by logistic regression modeling to determine the odds of recurrence in the second, third, and fourth pregnancies.

RESULTS

The final study comprised 24,819 women. The proportion of women who had a small-for-gestational-age infant in their first pregnancy was 9.4%, whereas the proportion of women who had a small-for-gestational-age infant in their second, third, and fourth pregnancies after the birth of a previous small-for-gestational-age infant were 20.5% (479 of 2338), 24.6% (63 of 256), and 30.4% (14 of 46), respectively. Regardless of parity, the odds of recurrence increased if the preceding infant was small-for-gestational-age. The odds of recurrence increased markedly if there was more than 1 previous small-for-gestational-age infant. In women with 3 previous small-for-gestational-age infants, the adjusted odds of another small-for-gestational-age infant were 66.00 (95% confidence interval, 11.35-383.76). Maternal age, body mass index, ethnicity, and smoking were significant risk factors for recurrent small-for-gestational-age. However, maternal diabetes mellitus or hypertension, either in a previous or current pregnancy, did not influence the risk of recurrence.

CONCLUSION

The risk of recurrence in a subsequent pregnancy increased if there was a previous small-for-gestational-age birth. Women with consecutive small-for-gestational-age infants were at the highest risk of recurrence. Our results highlight that women with a previous small-for-gestational-age infant are at a substantial risk of another small infant and need to be counseled and monitored appropriately.

Clinical Implications of Second and Third Trimester Surveillance Ultrasounds of Growth-Restricted Fetuses

Objective  We sought to investigate the positive predictive value of ultrasound-diagnosed fetal growth restriction (FGR) for estimating small for gestational age (SGA) at birth. Secondary objectives were to describe clinical interventions performed as a result of FGR diagnosis. Study Design  This was a retrospective cohort of pregnancies diagnosed with FGR over 3 years at a single institution. Maternal demographics, antenatal and delivery data, and neonatal data were collected. Descriptive statistics and linear regression were conducted. Results  We included 406 pregnancies with diagnosis of FGR in second or third trimester. Median birth weight percentile was 17 (interquartile range: 5-50) and only 35.0% of these fetuses were SGA at birth. The positive predictive value of a final growth ultrasound below the 10th percentile for SGA at birth was 56.9%. Patients averaged eight additional growth ultrasounds following FGR diagnosis. One hundred and fourteen (28.1%) received antenatal steroids prior to delivery, and 100% of those delivered after more than 7 days following administration. There were 6 fetal deaths and 14 neonatal deaths. Conclusion  In the majority of cases, pregnancies diagnosed with FGR during screening ultrasounds resulted in normally grown neonates and term deliveries. These patients may be receiving unnecessary ultrasounds and premature courses of corticosteroids.

Antenatal screening of small for gestational age: Impact on obstetrical management and neonatal outcomes in case of trial of labor after 37 weeks

OBJECTIVE

Antenatal screening of small fetuses for gestational age (SGA) is a public health challenge. The aim of this study is to assess the obstetrical management and the immediate neonatal outcomes, according to the antenatal screening of the SGA fetuses.

METHODS

We performed a retrospective study in a French tertiary care hospital between January 1, 2016 and December 31, 2018. Women were eligible if they had a monofetal pregnancy with a fetus in head presentation and a trial of labor after 37 weeks. A fetus was considered SGA when the estimated fetal weight was less than the 10^th percentile at the third trimester ultrasound. A newborn was considered hypotrophic when the birthweight was less than the 10th percentile.

RESULTS

8 153 newborns were included and 948 of the newborns were hypotrophic (308 were suspected for SGA, 640 were not suspected for SGA) and 7205 were eutrophic. Among the hypotrophic neonates, we observed no significant difference regarding the immediate neonatal outcomes between the two groups of fetuses suspected and not suspected for SGA. Among the fetuses not suspected for SGA, the rate of arterial umbilical cord pH below 7.10 was significantly higher in the hypotrophic newborns compared to the non hypotrophic newborns (4.7% vs 3.1%, p = 0.041).

CONCLUSION

In our population, unsuspected fetal hypotrophy may be associated with an increased risk of neonatal acidosis. These results emphasize the benefit of improving prenatal screening to identify the SGA fetuses.

Association Between Iatrogenic Delivery for Suspected Fetal Growth Restriction and Childhood School Outcomes

IMPORTANCE

Timely delivery of infants suspected of having fetal growth restriction (FGR) is a balance between preventing stillbirth and minimizing prematurity, particularly because many infants with suspected FGR have normal growth.

OBJECTIVE

To explore the association between iatrogenic delivery for suspected FGR and childhood school outcomes.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective whole-population cohort study linking perinatal data from births 32 weeks' or more gestation between January 1, 2003, to December 31, 2013, to developmental and educational test scores at preparatory school, and at school grades 3, 5, and 7 in Victoria, Australia. Follow-up was concluded in 2019.

EXPOSURES

Suspicion or nonsuspicion of FGR, presence or absence of iatrogenic delivery (defined as early induction of labor or cesarean delivery prior to labor) for suspected FGR, and presence or absence of small for gestational age (SGA).

MAIN OUTCOMES AND MEASURES

The coprimary outcomes were being in the bottom 10th percentile on 2 or more of 5 developmental domains at school entry and being below the national minimum standard on 2 or more of 5 educational domains in grades 3, 5, or 7.

RESULTS

In the birth population of 705 937 infants, the mean gestation at birth was 39.1 (SD, 1.5) weeks and the mean birth weight was 3426 (SD, 517) grams. The birth population linked to 181 902 children with developmental results and 425 717 children with educational results. Compared with infants with severe SGA (birth weight <3rd percentile) not suspected of having FGR, infants with severe SGA delivered for suspected FGR were born earlier (mean gestation, 37.9 weeks vs 39.4 weeks). They also had a significantly increased risk of poor developmental outcome at school entry (16.2% vs 12.7%; absolute difference, 3.5% [95% CI, 0.5%-6.5%]); adjusted odds ratio [aOR], 1.36 [95% CI, 1.07-1.74]) and poor educational outcomes in grades 3, 5, and 7 (for example, in grade 7: 13.4% vs 10.5%; absolute difference, 2.9% [95% CI, 0.4%-5.5%]); aOR, 1.33 [95% CI, 1.04-1.70]). There was no significant difference between infants with normal growth (birth weight ≥10th percentile) delivered for suspected FGR and those not suspected of having FGR in developmental outcome (8.6% vs 8.1%; absolute difference, 0.5% [95% CI, -1.1% to 2.0%]); aOR, 1.17 [95% CI, 0.95-1.45]) or educational outcome in grade 3, 5 or 7, despite being born earlier (mean gestation, 38.0 weeks vs 39.1 weeks).

CONCLUSIONS AND RELEVANCE

In this exploratory study conducted in Victoria, Australia, iatrogenic delivery of infants with severe SGA due to suspected FGR was associated with poorer school outcomes compared with infants with severe SGA not suspected of having FGR. Iatrogenic delivery of infants with normal growth due to suspected FGR was not associated with poorer school outcomes compared with infants with normal growth not suspected of having FGR.

Developing Novel Tests to Screen for Fetal Growth Restriction

Fetal growth restriction (FGR) is a major determinant of global morbidity and mortality. There is an unmet need for methods to stratify the pregnant population on the basis of FGR risk. Despite evolutionary divergence in mammalian reproduction, studies of genetically modified mice have identified biomarkers that have been validated in women, and a systematic screen for genes that control fetal growth in animals could help identify novel clinical biomarkers. Current approaches to biomarker identification using human samples include both targeted and discovery approaches (omics). Application of omic methods to the placenta and maternal blood has yielded promising results, but comes with logistical, experimental, and analytical challenges and all studies are limited by the lack of a gold standard for disease.

Routine Third Trimester Sonogram: Friend or Foe

Several risk factors for adverse pregnancy outcomes can be identified by a routine third trimester ultrasound scan. However, there is also potential for harm, anxiety, and additional health care costs through unnecessary intervention due to false positive results. The evidence base informing the balance of risks and benefits of universal screening is inadequate to fully inform decision making. However, data on the diagnostic effectiveness of universal ultrasound suggest that better methods are required to result in net benefit, with the exception of screening for presentation near term, where a clinical and economic case can be made for its implementation.

Reduced fetal growth velocity precedes antepartum fetal death

OBJECTIVES

To determine whether decreased fetal growth velocity precedes antepartum fetal death and to evaluate whether fetal growth velocity is a better predictor of antepartum fetal death compared to a single fetal biometric measurement at the last available ultrasound scan prior to diagnosis of demise.

METHODS

This was a retrospective, longitudinal study of 4285 singleton pregnancies in African-American women who underwent at least two fetal ultrasound examinations between 14 and 32 weeks of gestation and delivered a liveborn neonate (controls; n = 4262) or experienced antepartum fetal death (cases; n = 23). Fetal death was defined as death diagnosed at ≥ 20 weeks of gestation and confirmed by ultrasound examination. Exclusion criteria included congenital anomaly, birth at < 20 weeks of gestation, multiple gestation and intrapartum fetal death. The ultrasound examination performed at the time of fetal demise was not included in the analysis. Percentiles for estimated fetal weight (EFW) and individual biometric parameters were determined according to the Hadlock and Perinatology Research Branch/Eunice Kennedy Shriver National Institute of Child Health and Human Development (PRB/NICHD) fetal growth standards. Fetal growth velocity was defined as the slope of the regression line of the measurement percentiles as a function of gestational age based on two or more measurements in each pregnancy.

RESULTS

Cases had significantly lower growth velocities of EFW (P < 0.001) and of fetal head circumference, biparietal diameter, abdominal circumference and femur length (all P < 0.05) compared to controls, according to the PRB/NICHD and Hadlock growth standards. Fetuses with EFW growth velocity < 10^th percentile of the controls had a 9.4-fold and an 11.2-fold increased risk of antepartum death, based on the Hadlock and customized PRB/NICHD standards, respectively. At a 10% false-positive rate, the sensitivity of EFW growth velocity for predicting antepartum fetal death was 56.5%, compared to 26.1% for a single EFW percentile evaluation at the last available ultrasound examination, according to the customized PRB/NICHD standard.

CONCLUSIONS

Given that 74% of antepartum fetal death cases were not diagnosed as small-for-gestational age (EFW < 10^th percentile) at the last ultrasound examination when the fetuses were alive, alternative approaches are needed to improve detection of fetuses at risk of fetal death. Longitudinal sonographic evaluation to determine growth velocity doubles the sensitivity for prediction of antepartum fetal death compared to a single EFW measurement at the last available ultrasound examination, yet the performance is still suboptimal. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.