Does an obese prepregnancy body mass index influence outcome in pregnancies complicated by mild gestational hypertension remote from term?

Objectives This study was undertaken to determine the influence of increased prepregnancy body mass index (BMI) on pregnancy outcome in women with mild gestational hypertension remote from term. Study design A matched cohort design was used. A total of 365 pregnant women with mild gestational hypertension and a normal prepregnancy BMI (20-25 kg/m2) were matched 1:1 for gestational age at diagnosis, race and parity to 365 women with mild gestational hypertension, but an obese prepregnancy BMI (≥30 kg/m2). Results Matched characteristics were distributed as follows: gestational age at diagnosis 32.2 ± 2.4 weeks; race 80.8% white; parity 59.7% nulliparous. The rate of progression to preeclampsia was the primary endpoint of the study and was similar between the prepregnancy normal and obese BMI groups (37.8% vs 41.1%, P = .352). Birth weight at delivery (3033 ± 747 g vs 2833 ± 659 g, P< .001) and cesarean delivery rate (56.7% vs 40.3%, P< .001) were greater in the obese prepregnancy BMI group. Conclusion In patients with mild gestational hypertension remote from term, an obese prepregnancy BMI was associated with similar rates of progression to preeclampsia. Secondarily, an obese prepregnancy BMI was associated with higher birth weights and an increased incidence of cesarean delivery.