Intrauterine Fetal Growth Delay During Late Pregnancy After Maternal Gastric Bypass Surgery

Purpose  To investigate intrauterine fetal growth development and birth anthropometry of fetuses conceived after maternal gastric bypass surgery. Materials and Methods  Longitudinal cohort study describing longitudinal growth estimated by ultrasound on 43 singleton pregnancies after gastric bypass compared to 43 BMI-matched controls. Results  In fetuses after maternal gastric bypass surgery, growth percentiles decreased markedly from the beginning of the second trimester until the end of the third trimester (decrease of 3.1 fetal abdomen circumference percentiles (95 %CI 0.9 – 5.3, p = 0.007) per four gestational weeks). While in the second trimester, fetal anthropometric measures did not differ between the groups, the mean abdomen circumference percentiles appeared significantly smaller during the third trimester in offspring of mothers after gastric bypass (mean difference 25.1 percentiles, p  Conclusion  In fetuses conceived after maternal gastric bypass, intrauterine fetal growth distinctively declined in the second and third trimester, most prominently observed in fetal abdomen circumferences. Birth weight and placental weight at birth was significantly lower compared to BMI-matched controls, possibly due to altered maternal metabolic factors and comparable to mothers experiencing chronic hunger episodes.