Prediction of large-for-gestational-age neonate by routine third-trimester ultrasound

Multivariable prediction models for fetal macrosomia and large for gestational age: A systematic review

BACKGROUND

The identification of large for gestational age (LGA) and macrosomic fetuses is essential for counselling and managing these pregnancies.

OBJECTIVES

To systematically review the literature for multivariable prediction models for LGA and macrosomia, assessing the performance, quality and applicability of the included model in clinical practice.

SEARCH STRATEGY

MEDLINE, EMBASE and Cochrane Library were searched until June 2022.

SELECTION CRITERIA

We included observational and experimental studies reporting the development and/or validation of any multivariable prediction model for fetal macrosomia and/or LGA. We excluded studies that used a single variable or did not evaluate model performance.

DATA COLLECTION AND ANALYSIS

Data were extracted using the Checklist for critical appraisal and data extraction for systematic reviews of prediction modelling studies checklist. The model performance measures discrimination, calibration and validation were extracted. The quality and completion of reporting within each study was assessed by its adherence to the TRIPOD (Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis) checklist. The risk of bias and applicability were measured using PROBAST (Prediction model Risk Of Bias Assessment Tool).

MAIN RESULTS

A total of 8442 citations were identified, with 58 included in the analysis: 32/58 (55.2%) developed, 21/58 (36.2%) developed and internally validated and 2/58 (3.4%) developed and externally validated a model. Only three studies externally validated pre-existing models. Macrosomia and LGA were differentially defined by many studies. In total, 111 multivariable prediction models were developed using 112 different variables. Model discrimination was wide ranging area under the receiver operating characteristics curve (AUROC 0.56-0.96) and few studies reported calibration (11/58, 19.0%). Only 5/58 (8.6%) studies had a low risk of bias.

CONCLUSIONS

There are currently no multivariable prediction models for macrosomia/LGA that are ready for clinical implementation.

To know or not to know: Effect of third-trimester sonographic fetal weight estimation on outcomes of large-for-gestational age neonates

OBJECTIVE

The aim of the present study was to evaluate the impact of late third-trimester sonographic estimation of large for gestational age fetuses on pregnancy management and selected fetal and maternal adverse outcomes.

METHODS

A retrospective cohort study was conducted in a tertiary, university-affiliated medical center between 2015 and 2019. All singleton large-for-gestational-age neonates born during this period were included. The cohort was divided into two groups: neonates for whom fetal weight was estimated on late third trimester (<14 days before delivery) sonography and neonates with no recent fetal weight estimation. The groups were compared for pregnancy management strategies, rates of labor induction, cesarean deliveries, and maternal and neonatal outcomes.

RESULTS

A total of 1712 neonates were included in the study, among whom 791 (46.2%) had a late third-trimester fetal weight estimation (study group) and 921 (53.8%) did not (control group). Compared to the control group, the study group was characterized by higher rates of maternal primiparity (24.20% vs 19.20%, P = 0.013), higher maternal body mass index (26.0 ± 6.2 kg/m2 vs 24.7 ± 4.5 kg/m2, P = 0.002), more inductions of labor (29.84% vs 16.40%, P < 0.001) and cesarean deliveries (31.0% vs 19.97%, P < 0.001). There were no clinical differences in neonatal birth weight (4041 ± 256 g vs 3984 264 g, P < 0.001) and no significant differences between other neonatal outcomes, as rates of admission to the neonatal intensive care unit, jaundice, hypoglycemia, and shoulder dystocia.

CONCLUSION

Late third-trimester sonographic fetal weight estimation is associated with a higher rate of labor induction and planned and intrapartum cesarean deliveries. In this retrospective cohort study, those interventions did not lead to reduction in maternal or neonatal adverse outcomes.

Bigger babies: what happens in real practice in a non-academic UK center? Detection accuracy and outcomes with induction

BACKGROUND

There is emerging evidence of improved outcomes with induction of labour for pregnancies in which the baby is thought to be large. This trial identifies scan accuracy and the effect of intervention for pregnancies complicated by suspected large for gestational age (LGA) on customized chart outside an academic center.

METHODS

This is a retrospective cohort study of 3 groups of induced pregnancies; women with a suspected LGA fetus, women with diabetes (DM) and a control group (C) of women that underwent induction of labour on or after 280 days gestation. Data collection and analysis were prespecified. Scan accuracy and outcomes between the cohorts were compared.

RESULTS

Over 1 year there were 845 cases: LGA (128), DM (116) and control cases (601). Mean birthweights differed significantly. PPV of EFW for birthweight >90th centile on GROW chart, WHO chart, and >4 kg was 0.35-0.40. Projected birthweight of >4 kg significantly better predicted itself (AUROC 0.70, 0.74 and 0.80). Mean scan error was -5.2% and +15.6% for DM and LGA. Shoulder dystocia and neonatal morbidity were not increased in LGA despite the significant increase in AVD 28/128, 21.9% vs. 99/601, 16.5%, aOR 2.20 (1.07-4.5). SVD was significantly less likely LGA vs. C at 69/128, 53.9% vs. 413/601, 68.7% aOR 0.38 (95% CI: 0.21-0.70).

CONCLUSIONS

Third trimester EFW for bigger babies was poorly predictive of macrosomia. Fetal outcomes were good but women selected and induced as LGA had higher rates of hemorrhage and intervention.

Prediction of large-for-gestational-age at birth using fetal biometry in type 1 and type 2 diabetes: A retrospective cohort study

OBJECTIVE

To compare ultrasound-assessed fetal head circumference (HC), abdominal circumference (AC), HC/AC ratio, and estimated fetal weight (EFW) in prediction of large-for-gestational-age (LGA) at birth in pregnancies affected by type 1 (T1DM) and type 2 (T2DM) diabetes.

METHODS

This retrospective cohort study included all women with T1DM and T2DM giving birth to singletons between 2010 and 2019 at Aalborg University Hospital, Denmark. Ultrasound scans were performed at 16, 20, 28 and 34 weeks of pregnancy. LGA was defined as birth weight deviation of 15% or greater from the expected for gestational age (≥90th centile). Prediction of LGA was assessed by logistic regression adjusted for maternal characteristics and glycated hemoglobin (HbA1c) and area under the receiver operating characteristics curve (AUC).

RESULTS

Among 180 T1DM pregnancies, 118 (66%) had an LGA neonate at birth. At 28 weeks of pregnancy, they were predicted with AUCHC/AC = 0.67, AUCAC = 0.85, and AUCEFW = 0.86. The multivariate analysis did not improve the predictive performance of the HC/AC ratio or AC. Among 87 T2DM pregnancies, 36 (41%) had an LGA neonate at birth. At 28 weeks, they were predicted with AUCHC/AC = 0.73, AUCAC = 0.83, and AUCEFW = 0.87. In T2DM, the multivariate analysis significantly improved the predictive performance for both HC/AC ratio and AC from 20 weeks of pregnancy.

CONCLUSION

In T1DM and T2DM pregnancies, LGA is characterized by a general fetal overgrowth including both AC and HC. Therefore, AC and EFW perform better than the HC/AC ratio in the prediction of LGA. In T2DM, as opposed to T1DM, the predictive performance was improved by the inclusion of maternal characteristics and HbA1c in the analysis.

Accuracy of antenatal ultrasound in predicting large-for-gestational-age babies: population-based cohort study

BACKGROUND

Pregnancies with large-for-gestational-age fetuses are at increased risk of adverse maternal and neonatal outcomes. There is uncertainty about how to manage birth in such pregnancies. Current guidelines recommend a discussion with women of the pros and cons of options, including expectant management, induction of labor, and cesarean delivery. For women to make an informed decision about birth, antenatal detection of large for gestational age is essential.

OBJECTIVE

To investigate the ability of antenatal ultrasound scans to predict large for gestational age at birth.

STUDY DESIGN

In this retrospective cohort study, we analyzed data from a routinely collected database from the West Midlands, United Kingdom. We included pregnancies that had an antenatal ultrasound-estimated fetal weight between 35+0 and 38+0 weeks gestation for any indication and a subgroup where the reason for the scan was that the fetus was suspected to be big. Large for gestational age was defined as >90th customized GROW percentile for estimated fetal weight as well as neonatal weight. In addition, we tested the performance of an uncustomized standard, with Hadlock fetal weight >90th percentile and neonatal weight >4 kg. We calculated diagnostic characteristics for the whole population and groups with different maternal body mass indexes.

RESULTS

The study cohort consisted of 26,527 pregnancies, which, on average, had a scan at 36+4 weeks gestation and delivered 20 days later at a median of 39+3 weeks (interquartile range 15). In total, 2241 (8.4%) of neonates were large for gestational age by customized percentiles, of which 1459 (65.1%) had a scan estimated fetal weight >90th percentile, with a false positive rate of 8.6% and a positive predictive value of 41.0%. In the subgroup of 912 (3.4%) pregnancies scanned for a suspected large fetus, 293 (32.1%) babies were large for gestational age at birth, giving a positive predictive value of 50.3%, with a sensitivity of 77.1% and false positive rate of 36.0%. When comparing subgroups from low (<18.5 kg/m2) to high body mass index (>30 kg/m2), sensitivity increased from 55.6% to 67.8%, false positive rate from 5.2% to 11.5%, and positive predictive value from 32.1% to 42.3%. A total of 2585 (9.7%) babies were macrosomic (birthweight >4 kg), and of these, 1058 (40.9%) were large for gestational age (>90th percentile) antenatally by Hadlock's growth standard, with a false positive rate of 4.9% and a positive predictive value 41.0%. Analysis within subgroups showed better performance by customized than uncustomized standards for low body mass index (<18.5; diagnostic odds ratio, 23.0 vs 6.4) and high body mass index (>30; diagnostic odds ratio, 16.2 vs 8.8).

CONCLUSION

Late third-trimester ultrasound estimation of fetal weight for any indication has a good ability to identify and predict large for gestational age at birth and improves with the use of a customized standard. The detection rate is better when an ultrasound is performed for a suspected large fetus but at the risk of a higher false positive diagnosis. Our results provide information for women and clinicians to aid antenatal decision-making about the birth of a fetus suspected of being large for gestational age.

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.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Neonatal mortality risk of large-for-gestational-age and macrosomic live births in 15 countries, including 115.6 million nationwide linked records, 2000-2020

OBJECTIVE

We aimed to compare the prevalence and neonatal mortality associated with large for gestational age (LGA) and macrosomia among 115.6 million live births in 15 countries, between 2000 and 2020.

DESIGN

Population-based, multi-country study.

SETTING

National healthcare systems.

POPULATION

Liveborn infants.

METHODS

We used individual-level data identified for the Vulnerable Newborn Measurement Collaboration. We calculated the prevalence and relative risk (RR) of neonatal mortality among live births born at term + LGA (>90th centile, and also >95th and >97th centiles when the data were available) versus term + appropriate for gestational age (AGA, 10th-90th centiles) and macrosomic (≥4000, ≥4500 and ≥5000 g, regardless of gestational age) versus 2500-3999 g. INTERGROWTH 21st served as the reference population.

MAIN OUTCOME MEASURES

Prevalence and neonatal mortality risks.

RESULTS

Large for gestational age was common (median prevalence 18.2%; interquartile range, IQR, 13.5%-22.0%), and overall was associated with a lower neonatal mortality risk compared with AGA (RR 0.83, 95% CI 0.77-0.89). Around one in ten babies were ≥4000 g (median prevalence 9.6% (IQR 6.4%-13.3%), with 1.2% (IQR 0.7%-2.0%) ≥4500 g and with 0.2% (IQR 0.1%-0.2%) ≥5000 g). Overall, macrosomia of ≥4000 g was not associated with increased neonatal mortality risk (RR 0.80, 95% CI 0.69-0.94); however, a higher risk was observed for birthweights of ≥4500 g (RR 1.52, 95% CI 1.10-2.11) and ≥5000 g (RR 4.54, 95% CI 2.58-7.99), compared with birthweights of 2500-3999 g, with the highest risk observed in the first 7 days of life.

CONCLUSIONS

In this population, birthweight of ≥4500 g was the most useful marker for early mortality risk in big babies and could be used to guide clinical management decisions.

Alcohol exposure before and during pregnancy is associated with reduced fetal growth: the Safe Passage Study

BACKGROUND

Prenatal alcohol exposure (PAE) is a worldwide public health concern. While PAE is known to be associated with low birth weight, little is known about timing and quantity of PAE on fetal growth. This study investigated the association between periconceptional and prenatal alcohol exposure and longitudinal fetal growth, focusing on timing and quantity in a high exposure cohort.

METHODS

The Safe Passage Study was a prospective cohort study, including 1698 pregnant women. Two-dimensional transabdominal ultrasound examinations were performed to measure fetal femur length, abdominal and head circumference, and biparietal diameter, at three time points during pregnancy. Estimated fetal weight and Z-scores of all parameters were calculated. Trimester-specific alcohol exposure was assessed using the Timeline Followback method. To investigate the associations of specific timing of PAE and fetal growth, two models were built. One with alcohol exposure as accumulative parameter over the course of pregnancy and one trimester specific model, in which PAE was separately analyzed. Linear mixed models adjusted for potential confounders were applied with repeated assessments of both alcohol exposure and fetal growth outcomes.

RESULTS

This study demonstrated that periconceptional and prenatal alcohol exposure were associated with reduced fetal growth. Effect sizes are displayed as estimated differences (ED) in Z-score and corresponding 95% confidence intervals (95% CIs). When investigated as accumulative parameter, PAE was related to a smaller femur length (ED30; - 0.13 (95% CI; - 0.22; - 0.04), ED36; - 0.14 (95% CI; - 0.25; - 0.04)) and a smaller abdominal circumference (ED36; - 0.09 (95% CI; - 0.18; - 0.01)). Periconceptional alcohol exposure was associated with a smaller abdominal circumference (ED30; - 0.14 (95% CI; - 0.25; - 0.02), ED36; - 0.22 (95% CI; - 0.37; - 0.06)) and a smaller estimated fetal weight (ED36; - 0.22 (95% CI; - 0.38; - 0.05)). Second trimester alcohol exposure was associated with a smaller abdominal circumference (ED30; - 0.49 (95% CI; - 0.86; - 0.12), ED36; - 0.70 (95% CI; - 1.22; - 0.17)) and estimated fetal weight (ED30; - 0.54 (95% CI; - 0.94; - 0.14), ED36; - 0.69 (95% CI; - 1.25; - 0.14)). No additional association of binge drinking was found besides the already observed association of PAE and fetal growth.

CONCLUSIONS

This study demonstrated that PAE negatively affects fetal growth, in particular when exposed during the periconception period or in second trimester. Our results indicate that potential negative consequences of PAE are detectable already before birth. Therefore, healthcare providers should actively address and discourage alcohol use during pregnancy.

Fetal growth trajectories of small/large for gestational age infants in twin pregnancies

BACKGROUND

Birthweight is the most common and accessible parameter in assessing neonatal perinatal outcomes and in evaluating the intrauterine environment globally. Infants born too large or too small not only may alter the maternal mode of delivery but also may face other long-term disorders, such as metabolic diseases and neurodevelopmental delay. Studies have revealed different growth profiles of large-for-gestational-age and small-for-gestational-age fetuses in singleton pregnancies. However, currently, no research is focused on the growth trajectories of these infants during twin pregnancies, even though they are at a much higher risk of being small for gestational age.

OBJECTIVE

This study aimed to explore fetal growth trajectories of large-for-gestational-age and small-for-gestational-age infants in twin pregnancies to provide strategies for fetal growth management.

STUDY DESIGN

This was a case-control study of all noncomplicated twin pregnancies delivered after 36 weeks of gestation at the Peking University First Hospital between 2012 and 2021. Ultrasound data were recorded every 2 to 4 weeks until delivery. All the infants were divided into large-for-gestational-age, small-for-gestational-age, and appropriate-for-gestational-age groups. Longitudinal fetal growth (estimated fetal weight, abdominal circumference, etc.) was compared among the 3 groups using a linear mixed model, and other maternal and neonatal perinatal outcomes were compared. Receiver operating characteristic curves were used to explore optimal biometric parameters and gestational weeks for predicting small-for-gestational-age infants.

RESULTS

Here, 797 pregnant patients with 1494 infants were recruited, with 59 small-for-gestational-age infants, 1335 appropriate-for-gestational-age infants, and 200 large-for-gestational-age infants. The mean birthweights were 1985.34±28.34 g in small-for-gestational-age infants, 2662.08±6.60 g in appropriate-for-gestational-age infants, and 3231.24±11.04 g in large-for-gestational-age infants. The estimated fetal weight of the 3 groups differed from each other from week 26, with the small-for-gestational-age fetuses weighing 51.946 g less and the large-for-gestational-age fetuses weighing 35.233 g more than the appropriate-for-gestational-age fetuses. This difference increased with gestation; at 39 weeks, the small-for-gestational-age fetuses weighed 707.438 g less and the large-for-gestational-age fetuses weighed 614.182 g more than the appropriate-for-gestational-age fetuses (all P<.05). The small-for-gestational-age group had a significantly higher rate of hospitalization (89.9 %) and jaundice (40.7 %) than the appropriate-for-gestational-age group, whereas the hospitalization rate in the large-for-gestational-age group was significantly lower than the appropriate-for-gestational-age group (7.5% and 2.5%; all P<.05). The fetal weight of the small-for-gestational-age infants with adverse outcomes remained near the 10th percentile of the reference and fell below the 3rd percentile at 34 weeks of gestation. The estimated fetal weight after 30 weeks of gestation had a satisfactory diagnostic value in predicting small-for-gestational-age infants. At 30, 32, 34, and 36 weeks of gestation, the areas under the curve were 0.829, 0.840, 0.929, and 0.889 respectively.

CONCLUSION

The growth patterns of small-for-gestational-age, appropriate-for-gestational-age, and large-for-gestational-age twin fetuses diverged from 26 weeks of gestation and continued to increase until delivery; therefore, closer monitoring is suggested from 26 weeks of gestation for those carrying small fetuses.

Use and misuse of ultrasound in obstetrics with reference to developing countries

Maternal and neonatal health is one of the main global health challenges. Every day, approximately 800 women and 7,000 newborns die due to complications during pregnancy, delivery, and neonatal period. The leading causes of maternal death in sub-Saharan Africa are obstetric hemorrhage (28.8%), hypertensive disorders in pregnancy (22.1%), non-obstetric complications (18.8%), and pregnancy-related infections (11.5%). Diagnostic ultrasound examinations can be used in a variety of specific circumstances during pregnancy. Because adverse outcomes may also arise in low-risk pregnancies, it is assumed that routine ultrasound in all pregnancies will enable earlier detection and improved management of pregnancy complications. The World Health Organization (WHO) estimated in 1997 that 50% of developing countries had no access to ultrasound imaging, and available equipment was outdated or broken. Unfortunately, besides all the exceptional benefits of ultrasound in obstetrics, its inappropriate use and abuse are reported. Using ultrasound to view, take a picture, or determine the sex of a fetus without a medical indication can be considered ethically unjustifiable. Ultrasound assessment when indicated should be every woman's right in the new era. However, it is still only a privilege in some parts of the world. Investment in both equipment and human resources has been clearly shown to be cost-effective and should be an obligatory step in the improvement of health care. Well-developed health systems should guide developing countries, creating principles for the organization of the health system with an accent on the correct, legal, and ethical use of diagnostic ultrasound in pregnancy to avoid its misuse. The aim of the article is to present the importance of correct and appropriate use of ultrasound in obstetrics and gynecology with reference to developing countries.

Prediction of large-for-gestational-age infant by fetal growth charts and hemoglobin A1c level in pregnancy complicated by pregestational diabetes

OBJECTIVES

To compare the ability of three fetal growth charts (Fetal Medicine Foundation (FMF), Hadlock and National Institutes of Child Health and Human Development (NICHD) race/ethnicity-specific) to predict large-for-gestational age (LGA) at birth in pregnant individuals with pregestational diabetes, and to determine whether inclusion of hemoglobin A1c (HbA1c) level improves the predictive performance of the growth charts.

METHODS

This was a retrospective analysis of individuals with Type-1 or Type-2 diabetes with a singleton pregnancy that resulted in a non-anomalous live birth. Fetal biometry was performed between 28 + 0 and 36 + 6 weeks of gestation. The primary exposure was suspected LGA, defined as estimated fetal weight ≥ 90^th percentile using the Hadlock (Formula C), FMF and NICHD growth charts. The primary outcome was LGA at birth, defined as birth weight ≥ 90^th percentile, using 2017 USA natality reference data. The performance of the three growth charts to predict LGA at birth, alone and in combination with HbA1c as a continuous measure, was assessed using the area under the receiver-operating-characteristics curve (AUC), sensitivity, specificity, positive predictive value and negative predictive value.

RESULTS

Of 358 assessed pregnant individuals with pregestational diabetes (34% with Type 1 and 66% with Type 2), 147 (41%) had a LGA infant at birth. Suspected LGA was identified in 123 (34.4%) by the Hadlock, 152 (42.5%) by the FMF and 152 (42.5%) by the NICHD growth chart. The FMF growth chart had the highest sensitivity (77% vs 69% (NICHD) vs 63% (Hadlock)) and the Hadlock growth chart had the highest specificity (86% vs 76% (NICHD) and 82% (FMF)) for predicting LGA at birth. The FMF growth chart had a significantly higher AUC (0.79 (95% CI, 0.74-0.84)) for LGA at birth compared with the NICHD (AUC, 0.72 (95% CI, 0.68-0.77); P < 0.001) and Hadlock (AUC, 0.75 (95% CI, 0.70-0.79); P < 0.01) growth charts. Prediction of LGA improved for all three growth charts with the inclusion of HbA1c measurement in comparison to each growth chart alone (P < 0.001 for all); the FMF growth chart remained more predictive of LGA at birth (AUC, 0.85 (95% CI, 0.81-0.90)) compared with the NICHD (AUC, 0.79 (95% CI, 0.73-0.84)) and Hadlock (AUC, 0.81 (95% CI, 0.76-0.86)) growth charts.

CONCLUSIONS

The FMF fetal growth chart had the best predictive performance for LGA at birth in comparison with the Hadlock and NICHD race/ethnicity-specific growth charts in pregnant individuals with pregestational diabetes. Inclusion of HbA1c improved further the prediction of LGA for all three charts. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Establishing the Optimal Time for Induction of Labor in Women with Diet-Controlled Gestational Diabetes Mellitus: A Single-Center Observational Study

To determine the optimal week for labor induction in women with diet-controlled gestational diabetes mellitus by comparing differences in perinatal and neonatal outcomes of labor induction to expectant management at different gestational weeks. Methods: This was a retrospective analysis of a prospectively recruited cohort of 797 singleton pregnancies complicated by diet-controlled gestational diabetes mellitus that were diagnosed, treated, and delivered after 37 weeks in a tertiary, university-affiliated perinatal center between January 2016 and December 2021. Results: The incidence of neonatal complications was highest when delivery occurred at 37 weeks, whereas fetal macrosomia occurred mostly at 41 weeks (20.7%); the frequency of large for gestational age infants did not differ between the groups. Conversely, the best neonatal outcomes were observed at 40 weeks due to the lowest number of neonates requiring phototherapy for neonatal jaundice (1.7%) and the smallest proportion of neonates experiencing composite adverse neonatal outcomes defined as neonatal hypoglycemia, phototherapy, clavicle fracture, or umbilical artery pH < 7.15 (10.4%). Compared with expectant management, the risk for neonatal hypoglycemia was increased for induction at 39 weeks (adjusted odds ratio 12.29, 95% confidence interval 1.35−111.75, p = 0.026) and that for fetal macrosomia was decreased for induction at 40 weeks (adjusted odds ratio 0.11, 95% confidence interval 0.01−0.92, p = 0.041), after adjusting for maternal pre-pregnancy body mass index, nulliparity, and mean pregnancy A1c. Conclusions: The lowest rate of neonatal complications was observed at 40 weeks. Labor induction at 40 weeks prevented fetal macrosomia.

Competing-risks model for pre-eclampsia and adverse pregnancy outcomes

OBJECTIVE

The competing-risks model for assessment of risk for pre-eclampsia (PE) at 35-37 weeks' gestation identifies the majority of women who are at high risk of subsequent delivery with PE. We aimed to examine the incidence and relative risk of adverse pregnancy outcomes in patient groups stratified according to the estimated risk of delivery with PE.

METHODS

This was a prospective non-interventional, observational study in women with a singleton pregnancy attending for a routine hospital visit at 35 + 0 to 36 + 6 weeks' gestation. The risk of delivery with PE for each patient in the study population was estimated using the competing-risks model, combining the prior distribution of gestational age at delivery with PE and the likelihood from multiples of the median values of mean arterial pressure, placental growth factor and soluble fms-like tyrosine kinase-1. The patients were assigned to one of the following five risk categories: Group A, ≥ 1 in 2; Group B, 1 in 5 to 1 in 3; Group C, 1 in 20 to 1 in 6; Group D, 1 in 50 to 1 in 21; and Group E, < 1 in 50. The outcome measures were delivery with PE, gestational hypertension (GH), small-for-gestational age (SGA) at birth, delivery by Cesarean section, stillbirth, neonatal death, perinatal death and admission to the neonatal unit (NNU) for at least 48 h. In each risk category, the proportion of women with each adverse outcome was determined and relative risks (RR) were calculated as compared with the lowest-risk Group E.

RESULTS

In the study population of 29 035 women, 1.6%, 2.7%, 8.2%, 9.8% and 77.8% were categorized into Groups A, B, C, D and E, respectively. Compared with women in Group E, women in the higher-risk groups were more likely to have an adverse outcome. The RR of delivery with PE in Group A compared with Group E was 65.5 (95% CI, 54.1-79.1) and the respective values were 11.9 (95% CI, 9.1-15.5) for GH, 1.8 (95% CI, 1.5-2.1) for delivery by emergency Cesarean section, 1.5 (95% CI, 1.2-1.8) for delivery by elective Cesarean section, 8.9 (95% CI, 7.4-10.8) for SGA with birth weight < 3^rd percentile, 4.8 (95% CI, 4.3-5.4) for SGA with birth weight < 10^th percentile, 5.3 (95% CI, 1.4-20.5) for stillbirth and 3.4 (95% CI, 2.8-4.2) for NNU admission for ≥ 48 h. The RR for these pregnancy complications in higher-risk groups (vs Group E) was particularly high for cases with delivery within 2 weeks after assessment. In terms of SGA, both for birth weight < 10^th and < 3^rd percentiles, the trend in all cases was stronger than that observed when the analysis was confined to normotensive pregnancies. The rates of neonatal death were too small to allow meaningful comparisons between risk groups.

CONCLUSION

Pregnant women identified by the competing-risks model to be at high risk of PE are also at increased risk of GH, Cesarean section, stillbirth, SGA and NNU admission for ≥ 48 h. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Incidence changes in risk factors associated with the decreasing number of birth-related clavicle fractures in Finland: A nationwide retrospective birth cohort from 2004 to 2017

BACKGROUND

A clavicle fracture is one of the most common birth injuries. The objective of this study was to examine whether the decreased incidence of birth-related clavicle fractures in Finland is because of temporal changes in their predisposing factors.

METHODS

For this nationwide population-based study, we used the Finnish Medical Birth Register and the Care Register for Health Care databases. The study population included all singleton, live-born newborn born spontaneously or by vacuum-assisted delivery, in cephalic presentation ≥37⁺⁰ weeks of gestation. The incidences of clavicle fractures, pregnancy characteristics, and risk assessments for fracture were calculated and compared between two time periods: 2004-2010 and 2011-2017.

RESULTS

A total of 629 457 newborn were born vaginally between 2004 and 2017. The clavicle fracture incidence decreased from 17.6/1000 to 6.2/1000 live births. Shoulder dystocia, diabetes, and birthweight ≥4000 g were the strongest predisposing factors. The incidence of birthweight ≥4000 g decreased, meanwhile type 1 diabetes and shoulder dystocia remained stable and gestational diabetes, type 2 diabetes, and maternal obesity increased in the later study period. The incidence of clavicle fractures without known predisposing factors declined. Simultaneously, the cesarean birth rate remained stable (13.2%-13.1%), although the rate of vacuum-assisted deliveries increased (8.5%-9.5%).

DISCUSSION

The incidence of clavicle fractures decreased, even though the incidence of most risk factors remained stable or increased, and the cesarean birth rate remained stable. This decline may be related to the reduction of fracture incidence among deliveries without known risk factors, and the decrease in birthweight ≥4000 g.

Comparison of ophthalmic artery Doppler with PlGF and sFlt-1/PlGF ratio at 35-37 weeks' gestation in prediction of imminent pre-eclampsia

OBJECTIVE

To compare the predictive performance for delivery with pre-eclampsia (PE) at < 3 weeks and at any stage after assessment at 35 + 0 to 36 + 6 weeks' gestation of serum placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1)/PlGF ratio with that of a competing-risks model utilizing maternal risk factors, mean arterial pressure (MAP) and ophthalmic artery peak systolic velocity (PSV) ratio.

METHODS

This was a prospective observational study of women attending for a routine hospital visit at 35 + 0 to 36 + 6 weeks' gestation. This visit included recording of maternal demographic characteristics and medical history, ultrasound examination of fetal anatomy and growth, assessment of flow velocity waveforms from the maternal ophthalmic arteries and measurement of MAP, serum PlGF and serum sFlt-1. The performance of screening for delivery with PE at < 3 weeks and at any time after the examination was assessed using areas under the receiver-operating-characteristics curves and detection rates (DRs), at a 10% false-positive rate (FPR). McNemar's test was used to compare DRs, at a 10% FPR, between screening by PlGF concentration, the sFlt-1/PlGF concentration ratio and the competing-risks model utilizing maternal risk factors, MAP and ophthalmic artery PSV ratio. Model-based estimates of screening performance for different methods of screening were also produced.

RESULTS

The study population of 2338 pregnancies contained 75 (3.2%) cases that developed PE, including 30 (1.3%) that delivered with PE at < 3 weeks from assessment, and 2263 cases unaffected by PE. The DR of PE at < 3 weeks from assessment, at a 10% FPR, of sFlt-1/PlGF ratio (70.0% (95% CI, 50.6-85.3%)) was superior to that of PlGF (50.0% (95% CI, 31.3-68.7%)) or PSV ratio (56.7% (95% CI, 37.4-74.5%)) but inferior to that of the combination of maternal risk factors, MAP multiples of the median (MoM) and PSV ratio delta (96.7% (95% CI, 82.8-99.9%)). Similarly, the DR of PE at any stage after assessment of sFlt-1/PlGF ratio (62.7% (95% CI, 50.7-73.6%)) was superior to that of PlGF (52.0% (95% CI, 40.2-63.7%)) or PSV ratio (41.3% (95% CI, 30.1-53.3%)) but inferior to that of the combination of maternal risk factors, MAP MoM and PSV ratio delta (78.7% (95% CI, 67.7-87.3%)). The empirical results for DR at a 10% FPR were consistent with the modeled results, both for delivery with PE at < 3 weeks and at any time after assessment.

CONCLUSION

Ophthalmic artery Doppler in combination with maternal risk factors and blood pressure could potentially replace measurement of PlGF and sFlt-1/PlGF ratio in the prediction of imminent PE. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Ophthalmic artery Doppler at 35-37 weeks' gestation in pregnancies with small or growth-restricted fetuses

OBJECTIVES

First, to compare the ophthalmic artery peak systolic velocity (PSV) ratio at 35-37 weeks' gestation among women who delivered small-for-gestational-age (SGA) or growth-restricted (FGR) neonates in the absence of hypertensive disorders, women who developed pre-eclampsia (PE) or gestational hypertension (GH) and those without SGA, FGR, PE or GH. Second, to examine the association of PSV ratio with placental growth factor (PlGF) and mean arterial pressure (MAP). Third, to assess the associations of PSV ratio, PlGF and MAP with birth-weight Z-score and percentile.

METHODS

This was a prospective observational study in women attending for a routine hospital visit at 35 + 0 to 36 + 6 weeks' gestation. This visit included recording of maternal demographic characteristics and medical history, ultrasound examination of fetal anatomy and growth, and measurement of maternal ophthalmic artery PSV ratio, first (PSV1) and second (PSV2) peaks of systolic velocity, MAP and serum PlGF. The values of PSV ratio, MAP and PlGF were converted to multiples of the median (MoM) or delta values, and the median MoM or delta of these variables in the SGA, FGR, PE and GH groups were compared with those in the unaffected group. Regression analysis was used to examine the relationship of PSV ratio delta, PlGF MoM and MAP MoM with birth-weight Z-score after exclusion of PE and GH cases. Regression analysis was also used to examine the association of PSV ratio delta with log₁₀ PlGF MoM and log₁₀ MAP MoM.

RESULTS

The study population included 2287 pregnancies, of which 1954 (85.4%) were not affected by FGR, SGA, PE or GH, 49 (2.1%) were complicated by FGR in the absence of PE or GH, 160 (7.0%) had SGA in the absence of FGR, PE or GH, 60 (2.6%) had PE and 64 (2.8%) had GH. Compared with unaffected pregnancies, in both the FGR and SGA groups, the means of PSV ratio delta (0.042 (95% CI, 0.007-0.076) and 0.032 (95% CI, 0.016-0.049), respectively) and MAP MoM (1.028 (95% CI, 1.006-1.050) and 1.048 (95% CI, 1.035-1.060), respectively) were increased, while the mean of PlGF MoM was decreased (0.495 (95% CI, 0.393-0.622) and 0.648 (95% CI, 0.562-0.747), respectively). However, the magnitude of these changes was smaller than in the PE and GH groups. Ophthalmic artery waveform analysis revealed that the predominant feature of pregnancies complicated by SGA in the absence of hypertensive disorders was a reduction in PSV1, whereas, in those with hypertensive disorders, there was an increase in PSV2. In non-hypertensive pregnancies, there were linear inverse associations of PSV ratio delta and MAP MoM with birth-weight Z-score, with increased values in small neonates and decreased values in large neonates. There was a quadratic relationship between PlGF MoM and birth-weight Z-score, with low PlGF levels in small neonates and high PlGF levels in large neonates. There was a significant correlation of ophthalmic artery PSV ratio delta with both log₁₀ MAP MoM (0.124 (95% CI, 0.069-0.178)) and log₁₀ PlGF MoM (-0.238 (95% CI, -0.289 to -0.185)).

CONCLUSION

Assuming that the ophthalmic artery PSV ratio is a reflection of the interplay between cardiac output and peripheral vascular resistance, the linear association between PSV ratio and birth-weight Z-score in non-hypertensive pregnancies suggests the presence of a continuous physiological relationship between fetal size and cardiovascular response rather than a dichotomous relationship between high peripheral resistance and low cardiac output in small compared with non-small fetuses. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

STATIN trial: predictive performance of competing-risks model in screening for pre-eclampsia at 35-37 weeks' gestation

OBJECTIVE

To examine the predictive performance of a previously reported competing-risks model of screening for pre-eclampsia (PE) at 35-37 weeks' gestation by combinations of maternal risk factors, mean arterial pressure (MAP), uterine artery pulsatility index (UtA-PI), serum placental growth factor (PlGF) and serum soluble fms-like tyrosine kinase-1 (sFlt-1) in a validation dataset derived from the screened population of the STATIN study.

METHODS

This was a prospective third-trimester multicenter study of screening for PE in singleton pregnancies by means of a previously reported algorithm that combines maternal risk factors and biomarkers. Women in the high-risk group were invited to participate in a trial of pravastatin vs placebo, but the trial showed no evidence of an effect of pravastatin in the prevention of PE. Patient-specific risks of delivery with PE were calculated using the competing-risks model, and the performance of screening for PE by maternal risk factors alone and by various combinations of risk factors with MAP, UtA-PI, PlGF and sFlt-1 was assessed. The predictive performance of the model was examined by, first, the ability of the model to discriminate between the PE and no-PE groups using the area under the receiver-operating-characteristics curve (AUC) and the detection rate at a fixed false-positive rate of 10%, and, second, calibration by measurements of calibration slope and calibration-in-the-large.

RESULTS

The study population of 29 677 pregnancies contained 653 that developed PE. In screening for PE by a combination of maternal risk factors, MAP, PlGF and sFlt-1 (triple test), the detection rate at a 10% false-positive rate was 79% (95% CI, 76-82%) and the results were consistent with the data used for developing the algorithm. Addition of UtA-PI did not improve the prediction provided by the triple test. The AUC for the triple test was 0.923 (95% CI, 0.913-0.932), demonstrating very high discrimination between affected and unaffected pregnancies. Similarly, the calibration slope was 0.875 (95% CI, 0.831-0.919), demonstrating good agreement between the predicted risk and observed incidence of PE.

CONCLUSION

The competing-risks model provides an effective and reproducible method for third-trimester prediction of term PE. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Obstetric consequences of a false-positive diagnosis of large-for-gestational-age fetus

Objective

To compare delivery outcomes between true‐positive (TP) and false‐positive (FP) large‐for‐gestational‐age (LGA) fetuses, appropriate‐for‐gestational‐age (AGA) fetuses, and false‐negative (FN) LGA fetuses.

Methods

Retrospective cohort study of singleton pregnancies at risk for macrosomia without contraindication to vaginal delivery, receiving an ultrasound scan at 34–37 weeks of pregnancy.

Results

In all, 430 pregnancies were included: 155 TP LGA, 87 FP LGA, 177 AGA and 11 FN LGA newborns. Cesarean section rate during labor was significantly higher in FP LGA than in AGA (19% vs. 8.7%) but not significantly different between FP LGA and TP LGA (19% vs. 32.4%). Median birth weight z score was significantly higher in TP LGA (1.9) compared with the FP LGA and AGA (0.91 and 0.84, respectively), whereas no significant differences were found between FP LGA and AGA. Admission to a neonatal intensive care unit was significantly more frequent in TP LGA than AGA, whereas shoulder dystocia, postpartum hemorrhage, and third‐ to fourth‐degree perineal tears were similar between the different groups.

Conclusion

A false‐positive diagnosis of LGA fetus is associated with a significant increase of cesarean section during labor. Therefore, a suspicious ultrasound may result in reduction of the clinical threshold for the diagnosis of abnormal labor.

A false‐positive diagnosis of LGA fetus on ultrasound at 34–37 weeks is associated with a significant increase in cesarean section during labor.

Antenatal Fetal Size and Obesity in Five-Year-Old Children in a Large Cohort Created by Data Linkage

Background: What is not well understood is the gestational age at which the fetal size deviates from normal for children who develop obesity. Here we test the hypothesis that large-for-gestational age before birth is associated with increased risk for obesity in early childhood. Methods: In this retrospective study, routinely acquired antenatal ultrasound assessments in the first, second, and third trimester were linked to anthropometric measurements at 5.5 years. Results: There were 15,760 individuals, including 678 with obesity, 1955 overweight, and 1254 thin. Compared with children of healthy weight, children who had obesity were shorter in the first trimester [mean difference 0.19 z scores (0.10, 0.28)] and heavier in the second [mean difference z scores 0.15 (0.03, 0.27)] and third trimester [mean difference z scores 0.18 (0.05, 0.32)]. Children in the thin category were lighter compared with children of healthy weight in the third trimester and those in the overweight category were heavier compared with children of healthy weight in the third trimester. All associations were independent of birth weight. Conclusions: The difference in growth trajectories between children who have obesity compared with overweight or thin suggests different underlying mechanisms.

Diagnosis and Management of Gestational Diabetes Mellitus: An Overview of National and International Guidelines

Importance

Gestational diabetes mellitus (GDM) represents one of the most frequent complications of pregnancy and is associated with increased maternal and neonatal morbidity. Its incidence is rising, mostly due to an increase in maternal age and maternal obesity rate.

Objective

The aim of this study was to review and compare the recommendations of the most recently published guidelines on the diagnosis and management of this condition.

Evidence Acquisition

A descriptive review of guidelines from the National Institute for Health and Care Excellence (NICE), the International Federation of Gynecology and Obstetrics, the Australasian Diabetes in Pregnancy Society (ADIPS), the Society of Obstetricians and Gynecologists of Canada (SOGC), the American College of Obstetricians and Gynecologists (ACOG), the American Diabetes Association, and the Endocrine Society on gestational diabetes mellitus was carried out.

Results

The NICE guideline recommends targeted screening only for women with risk factors, whereas the International Federation of Gynecology and Obstetrics, ADIPS, SOGC, and the ACOG recommend screening for all pregnant women at 24 to 28 weeks of gestation in order to diagnose and effectively manage GDM; they also state that women with additional risk factors should be screened earlier (ie, in the first trimester) and retested at 24 to 28 weeks, if the initial test is negative. These guidelines describe similar risk factors for GDM and suggest the same thresholds for the diagnosis of GDM when using a 75-g 2-hour oral glucose tolerance test. Of note, the NICE only assesses the fasting and the 2-hour postprandial glucose levels for the diagnosis of GDM. Moreover, the SOGC and the ACOG do not recommend this test as the optimal screening method. The Endocrine Society alone, on the other hand, recommends the universal testing of all pregnant women for diabetes before 13 weeks of gestation or as soon as they attend the antenatal service and retesting at 24 to 28 weeks if the initial results are normal. In addition, there is a general consensus on the appropriate ultrasound surveillance of pregnancies complicated with GDM, and all the medical societies, except the ADIPS, recommend self-monitoring of capillary glucose to assess the glycemic control and set the same targets for fasting and postprandial glucose levels. There is also agreement that lifestyle modifications should be the first-line treatment; however, the reviewed guidelines disagree on the medical management of GDM. In addition, there are controversies regarding the timing of delivery, the utility of hemoglobin A_1c measurement, and the postpartum and lifelong screening for persistent hyperglycemia and type 2 diabetes. However, all the guidelines state that all women in pregnancies complicated by GDM should undergo a glycemic test at around 6 to 12 weeks after delivery. Finally, there is a universal consensus on the importance of breastfeeding and preconception screening before future pregnancies.

Conclusions

As GDM is an increasingly common complication of pregnancy, it is of paramount importance that inconsistencies between national and international guidelines should encourage research to resolve the issues of controversy and allow uniform international protocols for the diagnosis and management of GDM, in order to safely guide clinical practice and subsequently improve perinatal and maternal outcomes.

Third trimester ultrasound. A long-standing debate

Third trimester ultrasound has long been in obstetrics a topic of debate. This issue is framed in a historical debate on the effectiveness of routine obstetrical ultrasound and two opposing trends originated in America and Europe, respectively. Primary function of this ultrasound has been to detect fetal growth restriction, but no study has shown evidence of improving perinatal outcomes. Other secondary functions are detection of fetal abnormalities or evaluation of fetal presentation, and they have also shown no evidence. Despite the continuous appearance of works in this regard, health policies of both american and european trends have not been modified. Future seems to show a prolongation of the stalemate. Those health systems with a universal third trimester policy should propose an optimization of the test, in order to improve the benefits and obtain data for future studies that could resolve this longstanding debate.

The added value of umbilical vein flow in predicting fetal macrosomia at 36 weeks of gestation: A prospective cohort study

INTRODUCTION

Current models based on fetal biometry and maternal characteristics have a poor performance in predicting macrosomia. The primary aim of this study was to elucidate the diagnostic performance of fetal venous and arterial Dopplers in predicting macrosomia in the third trimester of pregnancy; the secondary aim was to build a multiparametric prediction model including pregnancy, ultrasound and Doppler characteristics able to predict macrosomia accurately.

MATERIAL AND METHODS

Prospective cohort study including 2156 singleton pregnancies scheduled for routine ultrasound assessment at 36 weeks of gestation. Fetal biometry, estimated fetal weight (EFW), pulsatility index of the uterine, umbilical, and middle cerebral arteries, cerebroplacental ratio and umbilical vein blood flow (UVBF) normalized for fetal abdominal circumference (UVBF/AC) were recorded. Primary outcome was the prediction of fetal macrosomia, defined as a birthweight >90th percentile; secondary outcome was the prediction of newborns >4000 g. Logistic regression and area under the curve (AUC) analyses were used to analyze the data.

RESULTS

Fetal macrosomia complicated 9.8% of pregnancies, and 7.7% of newborns had a birthweight >4000 g. At multivariate logistic regression analysis, maternal body mass index (adjusted odds ratio [aOR] 1.23), pregestational diabetes (aOR 1.83), a prior newborn with a birthweight >95th centile (aOR 1.49), EFW (aOR 2.23) and UVBF (aOR1.84) were independently associated with macrosomia, whereas gestational diabetes mellitus (P = .07) or any of the other Doppler parameters were not. EFW had an AUC of 0.750 and of 0.801 alone and in association with maternal characteristics for the prediction of macrosomia, respectively. The addition of UVBF to this model significantly improved the prediction of fetal macrosomia provided by maternal and ultrasound parameters with an AUC of 0.892 (De Long P = .044 and P = .0078, respectively). The predictive performance for birthweight >4000 g was similar and significantly improved when UVBF was included in the diagnostic algorithm.

CONCLUSIONS

Umbilical vein blood flow evaluation in the third trimester improves the diagnosis of fetal macrosomia. The optimal diagnostic performance for macrosomia is achieved by a multiparametric model including umbilical vein flow, maternal characteristics and EFW.

Prediction of Large-for-Gestational-Age Neonates by Different Growth Standards

OBJECTIVE

Compare the accuracy of the Hadlock, the NICHD, and the Fetal Medicine Foundation (FMF) charts to detect large-for-gestational-age (LGA) and adverse neonatal outcomes (as a secondary outcome).

METHODS

This is a secondary analysis from a prospective study that included singleton non-anomalous gestations with growth ultrasound at 26-36 weeks. LGA was suspected with estimated fetal weight > 90^th percentile by the NICHD, FMF, and Hadlock charts. LGA was diagnosed with birth weight > 90^th percentile. We tested the performance of these charts to detect LGA and adverse neonatal outcomes (neonatal intensive care unit admission, Ph < 7.1, Apgar <7 at 5 minutes, seizures, and neonatal death) by calculating the area under the curve, sensitivity, specificity, positive predictive value, and negative predictive value.

RESULTS

Of 1054 pregnancies, 123 neonates (12%) developed LGA. LGA was suspected in 58 (5.5%) by Hadlock, 229 (21.7%) by NICHD standard, and 231 (22%) by FMF chart. The NICHD standard (AUC: .79; 95% CI: .75-.83 vs. AUC .64; 95%CI: .6-.68; p = < .001) and FMF chart (AUC: .81 95% CI: .77-.85 vs. AUC .64; 95%CI: .6-.68; p = < .001) were more accurate than Hadlock. The FMF and NICHD had higher sensitivity (77.2 vs. 72.4 vs. 30.1%) but Hadlock had higher specificity for LGA (97.5 vs. 88.5 vs. 85.4%). All standards were poor predictors for adverse neonatal outcomes.

CONCLUSIONS

The NICHD and the FMF standards may increase the detection rate of LGA in comparison to the Hadlock chart. However, this may increase obstetrical interventions.

Ophthalmic artery Doppler in combination with other biomarkers in prediction of pre-eclampsia at 35-37 weeks' gestation

OBJECTIVE

To examine the potential value of maternal ophthalmic artery Doppler at 35-37 weeks' gestation in combination with the established biomarkers of pre-eclampsia (PE), including mean arterial pressure (MAP), uterine artery pulsatility index (UtA-PI), serum placental growth factor (PlGF) and serum soluble fms-like tyrosine kinase-1 (sFlt-1), in the prediction of subsequent development of PE.

METHODS

This was a prospective observational study in women attending for a routine hospital visit at 35 + 0 to 36 + 6 weeks' gestation. This visit included recording of maternal demographic characteristics and medical history, ultrasound examination for fetal anatomy and growth, assessment of flow velocity waveforms from the maternal ophthalmic arteries, and measurement of MAP, UtA-PI, serum PlGF and serum sFlt-1. The competing-risks model was used to estimate the individual patient-specific risks of delivery with PE at any time and at < 3 weeks after assessment by a combination of maternal demographic characteristics and medical history with biomarkers. The area under the receiver-operating-characteristics curve and detection rate (DR) of delivery with PE, at a 10% false-positive rate (FPR), in screening by combinations of maternal factors with ophthalmic artery second to first peak of systolic velocity ratio (PSV ratio), MAP, UtA-PI, serum PlGF and serum sFlt-1 were determined. The modeled performance of screening for PE was also estimated.

RESULTS

The study population of 2287 pregnancies contained 60 (2.6%) that developed PE, including 19 (0.8%) that delivered with PE at < 3 weeks after assessment. The PSV ratio improved the prediction of PE with delivery at any stage after assessment provided by maternal factors alone (from 25.4% to 50.6%), maternal factors and MAP (54.3% to 62.7%), maternal factors, MAP and PlGF (68.3% to 70.8%) and maternal factors, MAP, PlGF and sFlt-1 (75.7% to 76.7%), at a FPR of 10%. The PSV ratio also improved the prediction of PE with delivery at < 3 weeks after assessment provided by maternal factors alone (from 31.0% to 69.4%), maternal factors and MAP (74.1% to 83.4%), maternal factors, MAP and UtA-PI (77.1% to 85.0%) and maternal factors, MAP and PlGF (84.8% to 88.6%). The empirical results for DR at a 10% FPR were consistent with the modeled results. Screening by a combination of maternal factors with MAP and PSV ratio also detected 59.4% (95% CI, 58.6-82.5%) of cases of gestational hypertension with delivery at any stage after assessment, and 86.7% (95% CI, 82.4-100%) of those with delivery at < 3 weeks after assessment.

CONCLUSION

Ophthalmic artery Doppler could potentially improve the performance of screening for PE at 35-37 weeks, especially imminent PE with delivery within 3 weeks after assessment, but further studies are needed to validate this finding. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Prediction of newborn's body mass index using nationwide multicenter ultrasound data: a machine-learning study

BACKGROUND

This study introduced machine learning approaches to predict newborn's body mass index (BMI) based on ultrasound measures and maternal/delivery information.

METHODS

Data came from 3159 obstetric patients and their newborns enrolled in a multi-center retrospective study. Variable importance, the effect of a variable on model performance, was used for identifying major predictors of newborn's BMI among ultrasound measures and maternal/delivery information. The ultrasound measures included biparietal diameter (BPD), abdominal circumference (AC) and estimated fetal weight (EFW) taken three times during the week 21 - week 35 of gestational age and once in the week 36 or later.

RESULTS

Based on variable importance from the random forest, major predictors of newborn's BMI were the first AC and EFW in the week 36 or later, gestational age at delivery, the first AC during the week 21 - the week 35, maternal BMI at delivery, maternal weight at delivery and the first BPD in the week 36 or later. For predicting newborn's BMI, linear regression (2.0744) and the random forest (2.1610) were better than artificial neural networks with one, two and three hidden layers (150.7100, 154.7198 and 152.5843, respectively) in the mean squared error.

CONCLUSIONS

This is the first machine-learning study with 64 clinical and sonographic markers for the prediction of newborns' BMI. The week 36 or later is the most effective period for taking the ultrasound measures and AC and EFW are the best predictors of newborn's BMI alongside gestational age at delivery and maternal BMI at delivery.

Large-for-gestational age diagnosed during second-trimester anatomy ultrasound and association with gestational diabetes and large-for-gestational age at birth

OBJECTIVES

To determine if large-for-gestational age (LGA) diagnosed during second-trimester ultrasound examination is associated with the development of gestational diabetes mellitus (GDM) and LGA at birth.

METHODS

This was a retrospective cohort study of all pregnant women who underwent a second-trimester anatomy ultrasound examination between 18 and 22 weeks at our institution from 2012 to 2017. Patients were included in the LGA group if estimated fetal weight and/or fetal abdominal circumference was ≥ 90^th percentile for gestational age. Patients with a history of pre-GDM, multiple gestation, preterm delivery, use of betamethasone or fetal anomaly were excluded. The control group consisted of appropriate-for-gestational-age (AGA) pregnancies that were scanned at 18-22 weeks during the study period. AGA was defined as EFW > 10^th percentile and ≤ 89^th percentile. Prenatal and delivery records were reviewed and demographic and outcome variables were collected. Multivariable logistic regression models were applied to assess the impact of LGA diagnosed in the second trimester on the development of GDM and LGA at birth (birth weight ≥ 90^th percentile).

RESULTS

The study population included 756 patients with a LGA fetus and 756 with an AGA fetus on second-trimester ultrasound examination. In patients with a LGA fetus diagnosed during the second-trimester ultrasound examination, the incidence of GDM was 6.0% and the incidence of LGA at birth was 14.9%. Among patients with a LGA fetus in the second trimester, those who developed GDM or LGA at birth were significantly older and were more likely to be obese. Moreover, parity was associated with neonatal LGA (P = 0.0003) but not with GDM (P = 0.82). On multivariable logistic regression analysis with adjustment for age, parity, change in gestational body mass index, obesity, ethnicity and neonatal sex, LGA diagnosed during the second trimester was associated significantly with GDM (adjusted odds ratio (aOR), 2.54; 95% CI, 1.29-5.03; P = 0.007) and LGA at birth (aOR, 6.85; 95% CI, 3.60-13.05; P < 0.0001).

CONCLUSIONS

LGA diagnosed during second-trimester ultrasound examination is associated with the development of GDM and LGA at birth, independent of known risk factors, and could be used to identify these women earlier for intervention. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Comparison of Multivariable Logistic Regression and Other Machine Learning Algorithms for Prognostic Prediction Studies in Pregnancy Care: Systematic Review and Meta-Analysis

BACKGROUND

Predictions in pregnancy care are complex because of interactions among multiple factors. Hence, pregnancy outcomes are not easily predicted by a single predictor using only one algorithm or modeling method.

OBJECTIVE

This study aims to review and compare the predictive performances between logistic regression (LR) and other machine learning algorithms for developing or validating a multivariable prognostic prediction model for pregnancy care to inform clinicians' decision making.

METHODS

Research articles from MEDLINE, Scopus, Web of Science, and Google Scholar were reviewed following several guidelines for a prognostic prediction study, including a risk of bias (ROB) assessment. We report the results based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Studies were primarily framed as PICOTS (population, index, comparator, outcomes, timing, and setting): Population: men or women in procreative management, pregnant women, and fetuses or newborns; Index: multivariable prognostic prediction models using non-LR algorithms for risk classification to inform clinicians' decision making; Comparator: the models applying an LR; Outcomes: pregnancy-related outcomes of procreation or pregnancy outcomes for pregnant women and fetuses or newborns; Timing: pre-, inter-, and peripregnancy periods (predictors), at the pregnancy, delivery, and either puerperal or neonatal period (outcome), and either short- or long-term prognoses (time interval); and Setting: primary care or hospital. The results were synthesized by reporting study characteristics and ROBs and by random effects modeling of the difference of the logit area under the receiver operating characteristic curve of each non-LR model compared with the LR model for the same pregnancy outcomes. We also reported between-study heterogeneity by using τ2 and I2.

RESULTS

Of the 2093 records, we included 142 studies for the systematic review and 62 studies for a meta-analysis. Most prediction models used LR (92/142, 64.8%) and artificial neural networks (20/142, 14.1%) among non-LR algorithms. Only 16.9% (24/142) of studies had a low ROB. A total of 2 non-LR algorithms from low ROB studies significantly outperformed LR. The first algorithm was a random forest for preterm delivery (logit AUROC 2.51, 95% CI 1.49-3.53; I2=86%; τ2=0.77) and pre-eclampsia (logit AUROC 1.2, 95% CI 0.72-1.67; I2=75%; τ2=0.09). The second algorithm was gradient boosting for cesarean section (logit AUROC 2.26, 95% CI 1.39-3.13; I2=75%; τ2=0.43) and gestational diabetes (logit AUROC 1.03, 95% CI 0.69-1.37; I2=83%; τ2=0.07).

CONCLUSIONS

Prediction models with the best performances across studies were not necessarily those that used LR but also used random forest and gradient boosting that also performed well. We recommend a reanalysis of existing LR models for several pregnancy outcomes by comparing them with those algorithms that apply standard guidelines.

TRIAL REGISTRATION

PROSPERO (International Prospective Register of Systematic Reviews) CRD42019136106; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=136106.

Ophthalmic artery Doppler in prediction of pre-eclampsia at 35-37 weeks' gestation

OBJECTIVES

First, to examine the potential value of maternal ophthalmic artery Doppler at 35-37 weeks' gestation in the prediction of subsequent development of pre-eclampsia (PE), and, second, to examine the variability between repeat measurements in the same eye and variability in measurements between the two eyes.

METHODS

This was a prospective observational study in women attending for a routine hospital visit at 35 + 0 to 36 + 6 weeks' gestation. The visit included recording of maternal demographic characteristics and medical history and assessment of flow velocity waveforms from the maternal ophthalmic artery. Waveforms were obtained in sequence from the right eye, left eye and again from the right and then left eye. We recorded the average of the four measurements, two from each eye, for the following four indices: first peak of systolic velocity; second peak of systolic velocity; pulsatility index; and the ratio of the second to first peak of systolic velocity (PSV ratio). The measurements of the four indices were standardized to remove the effects of maternal characteristics and elements from the medical history. The competing-risks model was used to determine the detection rate (DR) of delivery with PE at any time and at < 3 weeks after assessment, at a 10% false-positive rate (FPR), in screening by maternal factors alone and a combination of maternal factors and the adjusted value of each of the four ophthalmic artery indices.

RESULTS

The study population of 2287 pregnancies contained 60 (2.6%) that developed PE, including 19 (0.8%) that delivered with PE at < 3 weeks after assessment. The DR, at 10% FPR, of delivery with PE at any time after assessment by maternal factors was 25.0% (95% CI, 14.7-37.9%), and this increased by 25 percentage points to 50.0% (95% CI, 36.8-63.2%) with the addition of the adjusted PSV ratio (P = 0.005); the respective values for delivery with PE at < 3 weeks after assessment were 31.6% (95% CI, 12.6-56.6%) and 57.9% (95% CI, 33.5-79.8%). The other ophthalmic artery indices did not improve the prediction provided by maternal factors alone. There was good correlation between the first and second measurements of PSV ratio from the same eye (right eye r = 0.823, left eye r = 0.840), but poorer correlation in the first and second measurements between the two eyes (first measurement r = 0.690, second measurement r = 0.682). In screening by maternal factors and PSV ratio for PE with delivery at any stage after assessment, the estimated DR, at 10% FPR, was 50.0% when the average of four measurements was used (two from each eye), 49.1% when the average of one measurement from each eye was used, 47.3% when the average of two measurements from the same eye was used, and 45.8% when only one measurement was used.

CONCLUSIONS

Ophthalmic artery PSV ratio at 35-37 weeks' gestation can predict subsequent delivery with PE, especially if this occurs within 3 weeks after assessment. In the assessment of ophthalmic artery Doppler, it is necessary to use the average of one measurement from each eye to minimize variability of measurements. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Universal third-trimester ultrasonic screening using fetal macrosomia in the prediction of adverse perinatal outcome: A systematic review and meta-analysis of diagnostic test accuracy

BACKGROUND

The effectiveness of screening for macrosomia is not well established. One of the critical elements of an effective screening program is the diagnostic accuracy of a test at predicting the condition. The objective of this study is to investigate the diagnostic effectiveness of universal ultrasonic fetal biometry in predicting the delivery of a macrosomic infant, shoulder dystocia, and associated neonatal morbidity in low- and mixed-risk populations.

METHODS AND FINDINGS

We conducted a predefined literature search in Medline, Excerpta Medica database (EMBASE), the Cochrane library and ClinicalTrials.gov from inception to May 2020. No language restrictions were applied. We included studies where the ultrasound was performed as part of universal screening and those that included low- and mixed-risk pregnancies and excluded studies confined to high risk pregnancies. We used the estimated fetal weight (EFW) (multiple formulas and thresholds) and the abdominal circumference (AC) to define suspected large for gestational age (LGA). Adverse perinatal outcomes included macrosomia (multiple thresholds), shoulder dystocia, and other markers of neonatal morbidity. The risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Meta-analysis was carried out using the hierarchical summary receiver operating characteristic (ROC) and the bivariate logit-normal (Reitsma) models. We identified 41 studies that met our inclusion criteria involving 112,034 patients in total. These included 11 prospective cohort studies (N = 9986), one randomized controlled trial (RCT) (N = 367), and 29 retrospective cohort studies (N = 101,681). The quality of the studies was variable, and only three studies blinded the ultrasound findings to the clinicians. Both EFW >4,000 g (or 90th centile for the gestational age) and AC >36 cm (or 90th centile) had >50% sensitivity for predicting macrosomia (birthweight above 4,000 g or 90th centile) at birth with positive likelihood ratios (LRs) of 8.74 (95% confidence interval [CI] 6.84-11.17) and 7.56 (95% CI 5.85-9.77), respectively. There was significant heterogeneity at predicting macrosomia, which could reflect the different study designs, the characteristics of the included populations, and differences in the formulas used. An EFW >4,000 g (or 90th centile) had 22% sensitivity at predicting shoulder dystocia with a positive likelihood ratio of 2.12 (95% CI 1.34-3.35). There was insufficient data to analyze other markers of neonatal morbidity.

CONCLUSIONS

In this study, we found that suspected LGA is strongly predictive of the risk of delivering a large infant in low- and mixed-risk populations. However, it is only weakly (albeit statistically significantly) predictive of the risk of shoulder dystocia. There was insufficient data to analyze other markers of neonatal morbidity.

How often do we identify fetal abnormalities during routine third-trimester ultrasound? A systematic review and meta-analysis

BACKGROUND

Routine third-trimester ultrasound is frequently offered to pregnant women to identify fetuses with abnormal growth. Infrequently, a congenital anomaly is incidentally detected.

OBJECTIVE

To establish the prevalence and type of fetal anomalies detected during routine third-trimester scans using a systematic review and meta-analysis.

SEARCH STRATEGY

Electronic databases (MEDLINE, Embase and the Cochrane library) from inception until August 2019.

SELECTION CRITERIA

Population-based studies (randomised control trials, prospective and retrospective cohorts) reporting abnormalities detected at the routine third-trimester ultrasound performed in unselected populations with prior screening. Case reports, case series, case-control studies and reviews without original data were excluded.

DATA COLLECTION AND ANALYSIS

Prevalence and type of anomalies detected in the third trimester. We calculated pooled prevalence as the number of anomalies per 1000 scans with 95% confidence intervals. Publication bias was assessed.

MAIN RESULTS

The literature search identified 9594 citations: 13 studies were eligible representing 141 717 women; 643 were diagnosed with an unexpected abnormality. The pooled prevalence of a new abnormality diagnosed was 3.68 per 1000 women scanned (95% CI 2.72-4.78). The largest groups of abnormalities were urogenital (55%), central nervous system abnormalities (18%) and cardiac abnormalities (14%).

CONCLUSION

Combining data from 13 studies and over 140 000 women, we show that during routine third-trimester ultrasound, an incidental fetal anomaly will be found in about 1 in 300 scanned women. This information should be taken into account when taking consent from women for third-trimester ultrasound and when designing and assessing cost of third-trimester ultrasound screening programmes.

TWEETABLE ABSTRACT

One in 300 women attending a third-trimester scan will have a finding of a fetal abnormality.

The value of fetal growth biometry velocities to predict large for gestational age (LGA) infants

Objective: The use of growth velocities derived from fetal biometrics have been suggested to improve prediction of large for gestational age (LGA). Our objective was to determine if ultrasonographic growth velocities (GV) for abdominal circumference (AC) and estimated fetal weight (EFW) improve the prediction of LGA infants when compared to Hadlock EFW.Methods: This was a secondary analysis of data from a prospective study of women referred for growth ultrasounds during the 3rd trimester. Growth velocities (GV) for AC (AC - GV) and EFW (EFW - GV) were derived from the difference in Z-scores between measurements at the time of anatomy survey (18-24 week) and third trimester ultrasound (26-36 weeks). Change in AC - GV and EFW - GV >90th %ile alone or in combination with Hadlock EFW >90th%ile were compared for prediction of a LGA neonate. The primary outcome was the sensitivity and specificity of the (1) Hadlock EFW >90%ile, (2) AC - GV, (3) EFW - GV, (4) Hadlock EFW + AC - GV, and (5) Hadlock EFW + EFW - GV for the prediction of neonatal LGA. Test characteristics and area under the ROC curve (AUC) were determined. The association between the ultrasound predicted growth and adverse neonatal outcome was assessed using logistic regression.Results: Of 630 women meeting inclusion criteria, 85 (13.5%) had LGA neonates. Hadlock EFW showed a better NPV (98.0%) and sensitivity (71.1%) when compared to AC - GV (NPV 87.5%, sensitivity 17.7%) and EFW - GV (NPV 88.0%, sensitivity 22.6%). Combining Hadlock EFW and AC-GV or EFW - GV did little to improve the test characteristics for the prediction of LGA (AUC 0.65 and 0.64, respectively). All five measurements were unable to predict a composite of adverse neonatal outcome or need for maternal cesarean delivery. Adjustment of the growth velocities for gestational age at anatomy scan or 3rd trimester growth scan did not change these results.Conclusion: AC and EFW growth velocities do not appear to improve the prediction of LGA infants when compared to using the third trimester Hadlock EFW.

Identification of large-for-gestational age fetuses using antenatal customized fetal growth charts: Can we improve the prediction of abnormal labor course?

INTRODUCTION

Fetal overgrowth is an acknowledged risk factor for abnormal labor course and maternal and perinatal complications. The objective of this study was to evaluate whether the use of antenatal ultrasound-based customized fetal growth charts in fetuses at risk for large-for-gestational age (LGA) allows a better identification of cases undergoing caesarean section due to intrapartum dystocia.

MATERIAL AND METHODS

An observational study involving four Italian tertiary centers was carried out. Women referred to a dedicated antenatal clinic between 35 and 38 weeks due to an increased risk of having an LGA fetus at birth were prospectively selected for the study purpose. The fetal measurements obtained and used for the estimation of the fetal size were biparietal diameter, head circumference, abdominal circumference and femur length, were prospectively collected. LGA fetuses were defined by estimated fetal weight (EFW) >95th centile either using the standard charts implemented by the World Health Organization (WHO) or the customized fetal growth charts previously published by our group. Patients scheduled for elective caesarean section (CS) or for elective induction for suspected fetal macrosomia or submitted to CS or vacuum extraction (VE) purely due to suspected intrapartum distress were excluded. The incidence of CS due to labor dystocia was compared between fetuses with EFW >95th centile according WHO or customized antenatal growth charts.

RESULTS

Overall, 814 women were eligible, however 562 were considered for the data analysis following the evaluation of the exclusion criteria. Vaginal delivery occurred in 466 (82.9 %) women (435 (77.4 %) spontaneous vaginal delivery and 31 (5.5 %) VE) while 96 had CS. The EFW was >95th centile in 194 (34.5 %) fetuses according to WHO growth charts and in 190 (33.8 %) by customized growth charts, respectively. CS due to dystocia occurred in 43 (22.2 %) women with LGA fetuses defined by WHO curves and in 39 (20.5 %) women with LGA defined by customized growth charts (p 0.70). WHO curves showed 57 % sensitivity, 72 % specificity, 24 % PPV and 91 % NPV, while customized curves showed 52 % sensitivity, 73 % specificity, 23 % PPV and 91 % NPV for CS due to labor dystocia.

CONCLUSIONS

The use of antenatal ultrasound-based customized growth charts does not allow a better identification of fetuses at risk of CS due to intrapartum dystocia.

Impact of biometric measurement error on identification of small- and large-for-gestational-age fetuses

OBJECTIVES

First, to obtain measurement-error models for biometric measurements of fetal abdominal circumference (AC), head circumference (HC) and femur length (FL), and, second, to examine the impact of biometric measurement error on sonographic estimated fetal weight (EFW) and its effect on the prediction of small- (SGA) and large- (LGA) for-gestational-age fetuses with EFW < 10^th and > 90^th percentile, respectively.

METHODS

Measurement error standard deviations for fetal AC, HC and FL were obtained from a previous large study on fetal biometry utilizing a standardized measurement protocol and both qualitative and quantitative quality-control monitoring. Typical combinations of AC, HC and FL that gave EFW on the 10^th and 90^th percentiles were determined. A Monte-Carlo simulation study was carried out to examine the effect of measurement error on the classification of fetuses as having EFW above or below the 10^th and 90^th percentiles.

RESULTS

Errors were assumed to follow a Gaussian distribution with a mean of 0 mm and SDs, obtained from a previous well-conducted study, of 6.93 mm for AC, 5.15 mm for HC and 1.38 mm for FL. Assuming errors according to such distributions, when the 10^th and 90^th percentiles are used to screen for SGA and LGA fetuses, respectively, the detection rates would be 78.0% at false-positive rates of 4.7%. If the cut-offs were relaxed to the 30^th and 70^th percentiles, the detection rates would increase to 98.2%, but at false-positive rates of 24.2%. Assuming half of the spread in the error distribution, using the 10^th and 90^th percentiles to screen for SGA and LGA fetuses, respectively, the detection rates would be 86.6% at false-positive rates of 2.3%. If the cut-offs were relaxed to the 15^th and 85^th percentiles, respectively, the detection rates would increase to 97.0% and the false-positive rates would increase to 6.3%.

CONCLUSIONS

Measurement error in fetal biometry causes substantial error in EFW, resulting in misclassification of SGA and LGA fetuses. The extent to which improvement can be achieved through effective quality assurance remains to be seen but, as a first step, it is important for practitioners to understand how biometric measurement error impacts the prediction of SGA and LGA fetuses. © 2019 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

Value of routine ultrasound examination at 35-37 weeks' gestation in diagnosis of non-cephalic presentation

OBJECTIVE

Undiagnosed non-cephalic presentation in labor carries increased risks for both the mother and baby. Routine pregnancy care based on maternal abdominal palpation fails to detect the majority of cases of non-cephalic presentation. The aim of this study was to report the incidence of non-cephalic presentation at a routine scan at 35 + 0 to 36 + 6 weeks' gestation and the subsequent management of such pregnancies.

METHODS

This was a retrospective analysis of prospectively collected data in 45 847 singleton pregnancies that had undergone routine ultrasound examination at 35 + 0 to 36 + 6 weeks' gestation. Patients with breech or transverse/oblique presentation were divided into two groups; first, those who would have elective Cesarean section for fetal or maternal indications other than the abnormal presentation, and, second, those who would potentially require external cephalic version (ECV). The latter group was reassessed after 1-2 weeks and, if there was persistence of abnormal presentation, the parents were offered the option of ECV or elective Cesarean section at 38-40 weeks' gestation. Multivariable logistic regression analysis was carried out to determine which of the factors from maternal and pregnancy characteristics provided a significant contribution in the prediction of, first, non-cephalic presentation at the 35 + 0 to 36 + 6-week scan, second, successful ECV from non-cephalic to cephalic presentation, and, third, spontaneous rotation from non-cephalic to cephalic presentation that persisted until delivery.

RESULTS

First, at 35 + 0 to 36 + 6 weeks, the fetal presentation was cephalic in 43 416 (94.7%) pregnancies, breech in 1987 (4.3%) and transverse or oblique in 444 (1.0%). Second, multivariable analysis demonstrated that the risk of non-cephalic presentation increased with increasing maternal age and weight, decreasing height and earlier gestational age at scan, was higher in the presence of placenta previa, oligohydramnios or polyhydramnios and in nulliparous than parous women, and was lower in women of South Asian or mixed racial origin than in white women. Third, 22% of cases of non-cephalic presentation were not eligible for ECV because of planned Cesarean section for indications other than the malpresentation. Fourth, of those eligible for ECV, only 48.5% (646/1332) agreed to the procedure, which was successful in 39.0% (252/646) of cases. Fifth, the chance of successful ECV increased with increasing maternal age and was lower in nulliparous than parous women. Sixth, in 33.9% (738/2179) of pregnancies with non-cephalic presentation in which successful ECV was not carried out, there was subsequent spontaneous rotation to cephalic presentation. Seventh, the chance of spontaneous rotation from non-cephalic to cephalic presentation increased with increasing interval between the scan and delivery, decreased with increasing birth-weight percentile, was higher in women of black than those of white racial origin, if presentation was transverse or oblique rather than breech and if there was polyhydramnios, and was lower in nulliparous than parous women and in the presence of placenta previa. Eighth, in 109 (0.3%) cephalic presentations, there was subsequent rotation to non-cephalic presentation and, in 41% of these, the diagnosis was made during labor. Ninth, of the total 2431 cases of non-cephalic presentation at the time of the scan, presentation at birth was cephalic in 985 (40.5%); in 738 (74.9%) this was due to spontaneous rotation and in 247 (25.1%) this was due to successful ECV. Tenth, prediction of non-cephalic presentation at the 35 + 0 to 36 + 6-week scan and successful ECV from maternal and pregnancy factors was poor, but prediction of spontaneous rotation from non-cephalic to cephalic presentation that persisted until delivery was moderately good and this could be incorporated in the counseling of women prior to ECV.

CONCLUSIONS

The problem of unexpected non-cephalic presentation in labor can, to a great extent, be overcome by a routine ultrasound examination at 35 + 0 to 36 + 6 weeks' gestation. The incidence of non-cephalic presentation at the 35 + 0 to 36 + 6-week scan was about 5%, but, in about 40% of these cases, the presentation at birth was cephalic, mainly due to subsequent spontaneous rotation and, to a lesser extent, as a consequence of successful ECV. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Value of routine ultrasound examination at 35-37 weeks' gestation in diagnosis of fetal abnormalities

OBJECTIVE

To investigate the potential value of routine ultrasound examination at 35-37 weeks' gestation in the diagnosis of previously unknown fetal abnormalities.

METHODS

This was a prospective study of 52 400 singleton pregnancies attending for a routine ultrasound examination at 35 + 0 to 36 + 6 weeks' gestation; all pregnancies had a previous scan at 18-24 weeks and 47 214 also had a scan at 11-13 weeks. We included pregnancies resulting in live birth or stillbirth but excluded those with known chromosomal abnormality. Abnormalities were classified according to the affected major organ system, and the type and incidence of new abnormalities were determined.

RESULTS

In the study population, the incidence of fetal abnormality was 1.9% (995/52 400), including 674 (67.7%) that had been diagnosed previously during the first and/or second trimester, 247 (24.8%) that were detected for the first time at 35-37 weeks and 74 (7.4%) that were detected for the first time postnatally. The most common abnormalities that were diagnosed during the first and/or second trimester and that were also observed at 35-37 weeks included ventricular septal defect, talipes, unilateral renal agenesis and/or pelvic kidney, hydronephrosis, duplex kidney, unilateral multicystic kidney, congenital pulmonary airway malformation, ventriculomegaly, cleft lip and palate, polydactyly and abdominal cyst or gastroschisis. The most common abnormalities first seen at 35-37 weeks were hydronephrosis, mild ventriculomegaly, ventricular septal defect, duplex kidney, ovarian cyst and arachnoid cyst. The incidence of abnormalities first seen at 35-37 weeks was 0.5% and those that were detected exclusively for the first time at this examination were ovarian cyst, microcephaly, achondroplasia, dacryocystocele and hematocolpos. The incidence of abnormalities first seen postnatally was 0.1% and the most common were isolated cleft palate, polydactyly or syndactyly and ambiguous genitalia or hypospadias; prenatal examination of the genitalia was not a compulsory part of the protocol.

CONCLUSIONS

A high proportion of fetal abnormalities are detected for the first time during a routine ultrasound examination at 35-37 weeks' gestation. Such diagnosis and subsequent management, including selection of timing and place for delivery and postnatal investigations, could potentially improve postnatal outcome. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Maternal and neonatal complications of fetal macrosomia: systematic review and meta-analysis

OBJECTIVE

To determine accurate estimates of risks of maternal and neonatal complications in pregnancies with fetal macrosomia by performing a systematic review of the literature and meta-analysis.

METHODS

A search of MEDLINE, EMBASE, CINAHL and The Cochrane Library was performed to identify relevant studies reporting on maternal and/or neonatal complications in pregnancies with macrosomia having a birth weight (BW) > 4000 g and/or those with birth weight > 4500 g. Prospective and retrospective cohort and population-based studies that provided data regarding both cases and controls were included. Maternal outcomes assessed were emergency Cesarean section (CS), postpartum hemorrhage (PPH) and obstetric anal sphincter injury (OASIS). Neonatal outcomes assessed were shoulder dystocia, obstetric brachial plexus injury (OBPI) and birth fractures. Meta-analysis using a random-effects model was used to estimate weighted pooled estimates of summary statistics (odds ratio (OR) and 95% CI) for each complication, according to birth weight. Heterogeneity between studies was estimated using Cochran's Q, I2 statistic and funnel plots.

RESULTS

Seventeen studies reporting data on maternal and/or neonatal complications in pregnancy with macrosomia were included. In pregnancies with macrosomia having a BW > 4000 g, there was an increased risk of the maternal complications: emergency CS, PPH and OASIS, which had OR (95% CI) of 1.98 (1.80-2.18), 2.05 (1.90-2.22) and 1.91 (1.56-2.33), respectively. The corresponding values for pregnancies with BW > 4500 g were: 2.55 (2.33-2.78), 3.15 (2.14-4.63) and 2.56 (1.97-3.32). Similarly, in pregnancies with a BW > 4000 g, there was an increased risk of the neonatal complications: shoulder dystocia, OBPI and birth fractures, which had OR (95% CI) of 9.54 (6.76-13.46), 11.03 (7.06-17.23) and 6.43 (3.67-11.28), respectively. The corresponding values for pregnancies with a BW > 4500 g were: 15.64 (11.31-21.64), 19.87 (12.19-32.40) and 8.16 (2.75-24.23).

CONCLUSION

Macrosomia is associated with serious maternal and neonatal adverse outcomes. This study provides accurate estimates of these risks, which can be used for decisions on pregnancy management. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.