The impact of maternal obesity on the incidence of adverse pregnancy outcomes in high-risk term pregnancies.

We investigated the impact of maternal obesity on pregnancy outcomes. Women with normal or obese body mass index (BMI) who delivered singleton infants at term were identified from a perinatal database. Rates of pregnancy complications and neonatal outcomes were compared between women with normal prepregnancy BMI (20 to 24.9 kg/m (2), N = 9171) and those with an obese prepregnancy BMI (> or = 30, N = 3744). Rates of pregnancy complications and neonatal outcomes were also evaluated by the level of obesity (obese [30 to 34.9 kg/m (2), N = 2106], severe obesity [35 to 39.9 kg/m (2), N = 953], and morbid obesity [> or = 40 kg/m (2), N = 685]). Rates of gestational diabetes (12.0% versus 3.7%, P < 0.001, odds ratio [95% confidence interval] = 3.5 [3.0, 4.1]) and gestational hypertension (30.9% versus 9.0%, P < 0.001, odds ratio [95% confidence interval] = 4.5 [4.1, 5.0]) were higher for obese versus normal BMI gravidas, respectively. Women with morbid or severe obesity had a greater incidence of gestational diabetes than women with an obese (30 to 34.9 kg/m (2)) or normal BMI (14.1%, 16.4%, 9.6%, and 3.7%, respectively; P < 0.05). The incidence of gestational hypertension increased with maternal BMI (9.0% normal, 25.5% obese, 33.7% severe, 43.4% morbid; all pairwise comparisons P < 0.05). Obese versus normal BMI was associated with more higher-level nursery admissions (8.2% versus 5.8%) and large-for-gestational age infants (12.3% versus 6.5%; P < 0.001). Obesity places a term pregnancy at risk for adverse maternal and neonatal outcomes.