The risk of adverse pregnancy outcomes in women who are overweight or obese

A secondary analysis was performed on data collected from nulliparous women with a singleton pregnancy enrolled in the Australian Collaborative Trial of Supplements with antioxidants Vitamin C and Vitamin E to pregnant women for the prevention of pre-eclampsia (ACTS). Women were categorized into three groups according to their body mass index (BMI): normal (BMI 18.5-24.9 kg/m2); overweight (BMI 25-29.9 kg/m2) and; obese (BMI 30-34.9 kg/m2). Obstetric and perinatal outcomes were compared by univariate and multivariate analyses.Of the 1661 women included, 43% were overweight or obese. Obese women were at increased risk of pre-eclampsia (relative risk (RR) 2.99 [95% confidence intervals (CI) 1.88, 4.73], p < 0.0001) and gestational diabetes (RR 2.10 [95%CI 1.17, 3.79], p = 0.01) compared with women with a normal BMI. Obese and overweight women were more likely to be induced and require a caesarean section compared with women of normal BMI (induction - RR 1.33 [95%CI 1.13, 1.57], p = 0.001 and 1.78 [95%CI 1.51, 2.09], p < 0.0001, caesarean section - RR 1.42 [95%CI 1.18, 1.70], p = 0.0002 and 1.63 [95%CI 1.34, 1.99], p < 0.0001). Babies of women who were obese were more likely to be large for gestational age (LFGA) (RR 2.08 [95%CI 1.47, 2.93], p < 0.0001) and macrosomic (RR 4.54 [95%CI 2.01, 10.24], p = 0.0003) compared with those of women with a normal BMI.The rate of overweight and obesity is increasing amongst the Australian obstetric population. Women who are overweight and obese have an increased risk of adverse pregnancy outcomes. In particular, obese women are at increased risk of gestational diabetes, pregnancy induced hypertension and pre-eclampsia. Effective preventative strategies are urgently needed.Current Controlled Trials ISRCTN00416244In Australia, the incidence of overweight and obesity is increasing in both women and men and amongst all age groups [1]. Between 2004 and 2005, approximately 15% of women aged 25 to 34 years of age were obese [1]. This age