Influence of maternal obesity on fetal growth at different periods of pregnancies with normal glucose tolerance.

AIM: We aimed to examine the influence of maternal obesity on fetal growth in utero at different periods of pregnancies with normal glucose tolerance.

METHODS: A retrospective cohort study on 356 pregnant women with normal glucose tolerance was conducted. The women were categorized by pre-pregnancy body mass index (BMI) as obese (OB; BMI ≥ 25.0 kg/m2 ) or non-obese (n-OB). Z-scores of the fetal abdominal circumference (AC) and the rate of fetal macrosomia (AC ≥ 90th percentile) at 19, 30, and 36 gestational weeks (GW) were compared between the two groups. Maternal demographics (age, parity, height, pre-pregnancy BMI, history of prior large-for-gestational-age delivery) were compared between the pregnancies with and without fetal macrosomia at each gestational age. Multiple logistic regression analysis was performed to determine the independent risk factors for fetal macrosomia.

RESULTS: Birthweights of the neonates were significantly higher in the OB group. Z-scores of the fetal AC were significantly higher in the OB group at 30 and 36 GW, while no significant difference was found at 19 GW. The rates of fetal macrosomia in the OB group were also higher at 30 and 36 GW, while maternal obesity was not associated with fetal macrosomia at 19 GW. Pre-pregnancy BMI was detected as the independent predictor of fetal macrosomia at 30 GW (odds ratio, 1.19 [95% CI]) and 36 GW (odds ratio, 1.13 [95% CI]).

CONCLUSION: Maternal pre-pregnancy obesity has a promoting effect on fetal growth from the third trimester through birth.