Objective: To examine the association between gestational weight gain and adverse maternal and infant outcomes among overweight women [body mass index (BMI) 26.0-29.0 kg/m(2)].
Methods: A population-based cohort study using birth certificate data (1990-2004) from 34,143 singleton, full-term deliveries to nulliparous, Missouri residents ages 18-35. Gestational weight gain was divided into three categories: below Institute of Medicine (IOM) recommendations (<15 lbs), within IOM recommendations (15-25 lbs), and above IOM recommendations (>25 lbs). Categories of 10-lb increments were also evaluated. The primary outcomes were preeclampsia, cesarean section, macrosomia, low birth weight (LBW), and perinatal death. Adjusted relative risks and 95% confidence intervals (CI) were calculated using Mantel-Haenszel pooled estimator.
Results: Compared to women who gained 15-25 lbs, women who gained <15 lbs were 0.8 (95% CI 0.6-1.0), 0.9 (0.8-1.0), 0.6 (0.5-0.8), and 1.7 (1.4-2.2) times as likely to have preeclampsia, cesarean section, macrosomia, and LBW, respectively. Conversely, women who gained >25 lbs were 1.7 (1.5-1.9), 1.3 (1.2-1.4), 2.1 (1.9-2.3), and 0.6 (0.5-0.7) times as likely to have preeclampsia, cesarean section, macrosomia, and LBW, respectively. The lowest risk of adverse outcomes was for women who gained in the 6-14 and 15-24 lb categories. There was no association between gestational weight gain and perinatal death.
Conclusions: Increasing gestational weight gain appears to decrease the risk of LBW but elevates the risks of preeclampsia, cesarean section, and macrosomia. Overweight women should gain within current IOM recommendations.