Visceral adiposity in the first half of pregnancy predicts newborn weight among adolescent mothers.

Objective: Maternal obesity is a strong risk factor for gestational diabetes mellitus and fetal macrosomia. We assessed the association between maternal visceral adiposity tissue (VAT) depth in the first half of pregnancy and both glucose tolerance in late pregnancy and newborn weight in pregnant adolescents.

Methods: We completed a prospective cohort study of 73 pregnant adolescents aged 10 to 19 years, without pre-pregnancy diabetes. VAT depth was measured by ultrasound at 12 to 20 weeks' gestation, followed by a two-hour 75-g oral glucose tolerance test at 36 to 39 weeks' gestation, to determine the glucose area under the curve (AUC glucose0-120). The association between VAT depth and newborn weight was evaluated by multiple linear regression analysis, controlling for maternal age, parity, smoking, gestational age at delivery, infant sex, pre-pregnancy BMI, weight gain in pregnancy, and fasting serum glucose at 36 to 39 weeks' gestation. The relation between VAT depth and AUC glucose0-120 was assessed by linear regression analysis, adjusting for maternal age, parity, smoking, pre-pregnancy BMI, and weight gain in pregnancy.

Results: A 1 cm increase in VAT depth was associated with a 206 g (95% CI 101 to 311) adjusted increase in mean birth weight. VAT depth and the other model covariates together explained more of the variance in birth weight (r(2) = 0.282; P < 0.001) than pre-pregnancy BMI with the other covariates in the same model (r(2) = 0.081; P = 0.076). All three glucose tolerance test measures were performed at 36 to 39 weeks' gestation in 51 of the 73 participants. The relationship between VAT depth and AUC glucose0-120 was not significant (P = 0.43).

Conclusion: VAT depth in the first half of pregnancy predicts newborn weight better than BMI, but is not associated with glucose tolerance in late pregnancy.