Gestational weight gain in obese women: Effects on perinatal and infant outcomes

Obesity increases risk for adverse pregnancy outcomes compared to women of normal prepregnancy weight, however less is known about how gestational weight gain (GWG) impacts obese women and their infants. To inform policy regarding GWG in obese women, I addressed three questions: (1) what risk is imposed by GWG in obese women, and does risk differ by National Heart Lung Blood Institute (NHLBI) obesity class; (2) what range of GWG optimizes healthy outcome for each obesity class with respect to parity, race and age; and (3) is current GWG policy meeting its goal of reducing risk in obese women and their infants?;Missouri Birth Certificate data was used to conduct the analyses. 143,585 obese women delivering live, full term, singleton infants were included in an analysis estimating risk and computing cumulative incidence (CI) of preeclampsia, cesarean section, small for gestational age (SGA) and large for gestational age (LGA) birth for 7 GWG categories within each obesity class. 493,565 obese and normal weight women delivering live, singleton infants were included in an analysis calculating CI of healthy outcome for each GWG category within each BMI class with respect to age, race and parity.;For obese women, GWG less than the currently recommended 15 lb, was associated with significantly lower risk of preeclampsia, cesarean delivery, and LGA birth and higher risk of SGA birth. Magnitude of association and CI for these outcomes differed by obesity class indicating that obese women are not a homogeneous group. GWG less than 15 lb maximized healthy outcome for obese women and differed by age, race and parity. Despite a higher CI of excess GWG women with normal BMI had greater CI of healthy outcome than obese women.;These findings do not support current GWG policy treating obese women as a homogeneous group, recommending GWG of "at least 15 lb" regardless of obesity class. Despite evidence that normal prepregnancy BMI reduces risk of adverse outcomes, prepregnancy obesity prevention policies are nonexistent. Policy recommendations include development of preconception health policies to reduce prepregnancy obesity and research focused on revising GWG recommendations to improve healthy outcome in obese women.