Fetal Weight

BackgroundPerinatal mortality and morbidity continue to be major global health challenges strongly associated with prematurity and reduced fetal growth, an issue of further interest given the mounting evidence that fetal growth in general is linked to degrees of risk of common noncommunicable diseases in adulthood. Against this background, WHO made it a high priority to provide the present fetal growth charts for estimated fetal weight (EFW) and common ultrasound biometric measurements intended for worldwide use.Methods and findingsWe conducted a multinational prospective observational longitudinal study of fetal growth in low-risk singleton pregnancies of women of high or middle socioeconomic status and without known environmental constraints on fetal growth. Centers in ten countries (Argentina, Brazil, Democratic Republic of the Congo, Denmark, Egypt, France, Germany, India, Norway, and Thailand) recruited participants who had reliable information on last menstrual period and gestational age confirmed by crown-rump length measured at 8-13 wk of gestation. Participants had anthropometric and nutritional assessments and seven scheduled ultrasound examinations during pregnancy. Fifty-two participants withdrew consent, and 1,387 participated in the study. At study entry, median maternal age was 28 y (interquartile range [IQR] 25-31), median height was 162 cm (IQR 157-168), median weight was 61 kg (IQR 55-68), 58% of the women were nulliparous, and median daily caloric intake was 1,840 cal (IQR 1,487-2,222). The median pregnancy duration was 39 wk (IQR 38-40) although there were significant differences between countries, the largest difference being 12 d (95% CI 8-16). The median birthweight was 3,300 g (IQR 2,980-3,615). There were differences in birthweight between countries, e.g., India had significantly smaller neonates than the other countries, even after adjusting for gestational age. Thirty-one women had a miscarriage, and three fetuses had intrauterine death. The 8,203 sets of ultrasound measurements were scrutinized for outliers and leverage points, and those measurements taken at 14 to 40 wk were selected for analysis. A total of 7,924 sets of ultrasound measurements were analyzed by quantile regression to establish longitudinal reference intervals for fetal head circumference, biparietal diameter, humerus length, abdominal circumference, femur length and its ratio with head circumference and with biparietal diameter, and EFW. There was asymmetric distribution of growth of EFW: a slightly wider distribution among the lower percentiles during early weeks shifted to a notably expanded distribution of the higher percentiles in late pregnancy. Male fetuses were larger than female fetuses as measured by EFW, but the disparity was smaller in the lower quantiles of the distribution (3.5%) and larger in the upper quantiles (4.5%). Maternal age and maternal height were associated with a positive effect on EFW, particularly in the lower tail of the distribution, of the order of 2% to 3% for each additional 10 y of age of the mother and 1% to 2% for each additional 10 cm of height. Maternal weight was associated with a small positive effect on EFW, especially in the higher tail of the distribution, of the order of 1.0% to 1.5% for each additional 10 kg of bodyweight of the mother. Parous women had heavier fetuses than nulliparous women, with the disparity being greater in the lower quantiles of the distribution, of the order of 1% to 1.5%, and diminishing in the upper quantiles. There were also significant differences in growth of EFW between countries. In spite of the multinational nature of the study, sample size is a limiting factor for generalization of the charts.ConclusionsThis study provides WHO fetal growth charts for EFW and common ultrasound biometric measurements, and shows variation between different parts of the world.

BackgroundThe early life course is assumed to be a critical phase for childhood obesity; however the significance of single factors and their interplay is not well studied in childhood populations.ObjectivesThe investigation of pre-, peri- and postpartum risk factors on the risk of obesity at age 2 to 9.MethodsA case-control study with 1,024 1:1-matched case-control pairs was nested in the baseline survey (09/2007-05/2008) of the IDEFICS study, a population-based intervention study on childhood obesity carried out in 8 European countries in pre- and primary school settings. Conditional logistic regression was used for identification of risk factors.ResultsFor many of the investigated risk factors, we found a raw effect in our study. In multivariate models, we could establish an effect for gestational weight gain (adjusted OR = 1.02; 95%CI 1.00-1.04), smoking during pregnancy (adjusted OR = 1.48; 95%CI 1.08-2.01), Caesarian section (adjusted OR = 1.38; 95%CI 1.10-1.74), and breastfeeding 4 to 11 months (adjusted OR = 0.77; 95%CI 0.62-0.96). Birth weight was related to lean mass rather than to fat mass, the effect of smoking was found only in boys, but not in girls. After additional adjustment for parental BMI and parental educational status, only gestational weight gain remained statistically significant. Both, maternal as well as paternal BMI were the strongest risk factors in our study, and they confounded several of the investigated associations.ConclusionsKey risk factors of childhood obesity in our study are parental BMI and gestational weight gain; consequently prevention approaches should target not only children but also adults. The monitoring of gestational weight seems to be of particular importance for early prevention of childhood obesity.

Compelling evidence indicates that stress in utero, as manifested by low birth weight (LBW), increases the risk of metabolic syndrome in adulthood. Singletons conceived by assisted reproductive technology (ART) display a significant increase in LBW risk and ART offspring have a different metabolic profile starting at birth. Here, used mouse as a model, we found that ART resulted in reduced fetal weight and placental overgrowth at embryonic day 18.5 (E18.5). The ART placentae exhibited histomorphological alterations with defects in placental layer segregation and glycogen cells migration at E18.5. Further, ART treatments resulted in downregulation of a majority of placental nutrient transporters and reduction in placental efficiency. Moreover, the ART placentae were associated with increased methylation levels at imprinting control regions of H19, KvDMR1 and disrupted expression of a majority of imprinted genes important for placental development and function at E18.5. Our results from the mouse model show the first piece of evidence that ART treatment could affect fetal growth by disrupting placental development and function, suggests that perturbation of genomic imprinting resulted from embryo manipulation may contribute to these problems.

ObjectiveTo compare the predictive performance of intertwin estimated fetal weight (EFW) discordance and EFW centile calculated according to either the Fetal Medicine Foundation (FMF) singleton or twin-specific fetal growth charts for adverse perinatal outcome in dichorionic and monochorionic twin pregnancies.MethodsThis was a retrospective multicenter cohort study of twin pregnancies managed between January 2013 and December 2023 at three tertiary fetal medicine centers in the UK, Italy and Belgium. Twin pregnancies in which an obstetric ultrasound exam was performed to obtain fetal biometry within 2 weeks before live birth or diagnosis of intrauterine fetal demise of one or both twins were included. Cases with anastomotic complications were excluded. The primary outcome was a composite adverse perinatal outcome (CAPO), defined as stillbirth (intrauterine fetal demise ≥ 22 weeks) of at least one cotwin and/or iatrogenic early preterm birth (delivery ResultsThe study analyzed 1294 dichorionic and 487 monochorionic twin pregnancies. For the prediction of CAPO, intertwin EFW discordance in dichorionic twins achieved an AUC of 0.93 (95% CI, 0.89-0.98), compared with 0.83 (95% CI, 0.77-0.90) (P = 0.001) and 0.87 (95% CI, 0.81-0.93) (P = 0.017) for EFW centile based on singleton and twin-specific growth charts, respectively. Likewise, intertwin EFW discordance achieved an AUC of 0.95 (95% CI, 0.92-0.97) for predicting CAPO in monochorionic twins, outperforming EFW centile based on singleton charts (AUC, 0.80 (95% CI, 0.73-0.87); P ConclusionsIntertwin EFW discordance is a more reliable predictor of the composite outcome of stillbirth in at least one cotwin and/or iatrogenic early preterm birth in twin pregnancies than is EFW centile based on either singleton or twin-specific growth charts. This approach addresses the limitations of using different fetal growth reference charts that rely on arbitrary cut-offs. Following external validation, the use of intertwin EFW discordance prediction algorithms may potentially enhance risk stratification to improve clinical outcomes in twin pregnancies. © 2025 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.