Maternal abdominal subcutaneous fat thickness as a predictor for adverse pregnancy outcome: a longitudinal cohort study.

Objective: To assess maternal abdominal subcutaneous fat thickness (SFT) measured by ultrasound as an independent predictor of adverse pregnancy outcomes.

Design: A prospective longitudinal cohort study performed on pregnancies delivered between 2012 and 2014.

Setting: Sydney, Australia.

Population: About 1510 pregnant women attending routine obstetric ultrasounds.

Methods: Maternal SFT was measured on routine ultrasounds at 11-14 weeks' gestation (SFT1) and 18-22 weeks' gestation (SFT2). SFT measurements were assessed for estimating risks for obesity-related pregnancy outcomes using logistic regression modelling adjusted for maternal age, parity, smoking status and body mass index (BMI).

Main Outcome Measures: Hypertensive disease, gestational diabetes, caesarean section, low birthweight, preterm delivery, neonatal respiratory distress, Apgar scores, and admission to a neonatal intensive care unit.

Results: SFT1 and SFT2 were measured on 1461 and 1363 women, respectively. Mean thickness (range) were 21.2 mm (6.9-73.9) for SFT1 and 20.3 mm (7.5-68.0) for SFT2. Complete outcome data were available for 1385 pregnancies. In all, 54% of the women were overweight/obese. The SFT measures decreased from early to mid-pregnancy in overweight/obese women. There was moderate correlation between BMI and SFT1 (R(2) = 0.56) and BMI and SFT2 (R(2) = 0.55). In a multivariate model, SFT1 and SFT2 were better predictors for adverse pregnancy outcomes than BMI.

Conclusion: Maternal SFT is a significant independent predictor of adverse pregnancy outcomes. Incorporation of SFT into future models for adverse pregnancy outcome may prove valuable.