Objective: To compare pregnancy outcomes between morbidly obese and nonobese women and to determine the effect of gestational weight gain on pregnancy outcome in morbidly obese women.
Methods: A retrospective cohort study was conducted comparing 613 morbidly obese and 11,313 nonobese women who were delivered of a singleton live birth. Morbid obesity was defined as a body mass index greater than 35. The incidence of selected perinatal and neonatal outcomes was assessed for the two groups. Multiple logistic regression analysis was used to evaluate the association between morbid obesity and various measures of outcome while controlling for potential confounders. A subanalysis of the morbidly obese patients was performed to assess the effect of gestational weight gain on pregnancy outcome.
Results: Morbidly obese patients were more likely to experience pregnancy complications including diabetes, hypertension, preeclampsia, and arrest-of-labor disorders; however, these were not affected by gestational weight gain. Morbidly obese patients were more likely to experience fetal distress and meconium and to undergo cesarean delivery than their nonobese counterparts (P < .05). Weight gains of more than 25 lb were associated strongly with birth of a large for gestational age (LGA) neonate (P < .01); however, poor weight gain did not appear to increase the risk of delivery of a low birth weight neonate.
Conclusion: Gestational weight gain was not associated with adverse perinatal outcome, but it did influence neonatal outcome. To reduce the risk of delivery of an LGA newborn, the optimal gestational weight gain for morbidly obese women should not exceed 25 lb.