Maternal obesity and excess of fetal growth in pre-eclampsia

To assess whether the reported excess of large for gestational age (LGA) neonates in pre-eclamptic women delivering at term is attributable to maternal obesity.

Population-based observational study including 77,294 singleton pregnancies registered in the Medical Birth Registry of Norway between 2007 and 2010.

Comparison of birthweight percentiles and z-scores between women with and without pre-eclampsia.

Odds ratio (OR) of LGA and z-scores of birthweight in relation to pre-eclampsia.

Pre-eclamptic women delivering at term had increased risk of having LGA neonates. Unadjusted ORs with 95% confidence interval (95% CI) of LGA above the 90th and 95th birthweight centiles were 1.4, 95% CI 1.2-1.6 and 1.6, 95% CI 1.3-1.9, respectively. The excess of LGA persisted after including gestational diabetes and diabetes types 1 and 2 in a multivariate analysis (corresponding ORs 1.3, 95% CI 1.1-1.5 and 1.4, 95% CI 1.2-1.7), but disappeared after adjusting for maternal prepregnant body mass index (ORs 1.1, 95% CI 0.9-1.2 and 1.1, 95% CI 0.9-1.3).

This study suggests accelerated fetal growth in a subset of pre-eclamptic women delivering at term. The excess of LGA neonates is attributable to maternal obesity among pre-eclamptic women delivering at term. The maternal obesity epidemic may lead to an increased prevalence of both pre-eclampsia and LGA neonates among women delivering at term.