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

To investigate intrauterine fetal growth development and birth anthropometry of fetuses conceived after maternal gastric bypass surgery.

Longitudinal cohort study describing longitudinal growth estimated by ultrasound on 43 singleton pregnancies after gastric bypass compared to 43 BMI-matched controls.

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 < 0.001). Similar tendencies have been observed in estimated fetal weight resulting in significantly more SGA offspring at delivery in the gastric bypass group. In children born after maternal gastric bypass surgery, weight percentiles (32.12^th vs. 55.86^th percentile, p < 0.001) as well as placental weight (525.2 g vs. 635.7 g, p < 0.001) were significantly reduced compared to controls.

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.