Gestational weight gain and risk of infant death in the United States

We examined the association of prepregnancy body mass index (BMI) and gestational weight gain (GWG) with risk of death during infancy using the Institute of Medicine's (IOM's) Pregnancy Weight Gain Guidelines.

We obtained maternal and infant data for 2004-2008 from 159,244 women with a singleton, full-term, live birth in the 41 states that participated in phase 5 of the Pregnancy Risk Assessment Monitoring System. We fit logistic regression models to estimate the association between prepregnancy BMI, GWG, and risk of death during infancy, controlling for confounders.

Only 34% of women gained the IOM-recommended amount of weight during pregnancy. Infants born to underweight, normal-weight, and overweight women with inadequate GWG had odds of mortality during infancy that were 6.18, 1.47, and 2.11 times higher, respectively, than those of infants born to women with adequate GWG. Infants born to obese women with excessive weight gain had a 49% decreased likelihood of mortality.

A significant association exists between inadequate GWG and infant death that weakens with increasing prepregnancy BMI; weight gain beyond the recommended amount appears to be protective against infant mortality.