Background: Maternal obesity has been associated with poor lactation in animal models, but the results of related research in humans are inconclusive.
Objective: We tested the hypothesis that women who are obese before pregnancy or who gain excessive weight during pregnancy are less likely to initiate and maintain breast-feeding than are their normal-weight counterparts.
Design: We analyzed 124 151 mother-infant pairs from the Pediatric Nutrition Surveillance System and the Pregnancy Nutrition Surveillance System. Body mass index (BMI) before pregnancy and gestational weight gain were categorized according to guidelines from the Institute of Medicine. Multiple logistic regression was used to identify the association between maternal obesity and breast-feeding initiation (n = 51 329), and multiple linear regression was used to examine the effect of maternal obesity on breast-feeding duration among women who initiated breast-feeding (n = 13 234).
Results: Regardless of gestational weight gain, obese women were less likely to initiate breast-feeding than were women with a normal BMI before pregnancy who also gained the recommended weight during pregnancy. Maternal BMI before pregnancy and gestational weight gain were each independently associated with duration of breast-feeding. Women who were obese before pregnancy breast-fed approximately 2 wk less than did their normal-weight counterparts, and women who either failed to reach or exceeded the recommended gestational weight gain breast-fed approximately 1 wk less than did those who gained the recommended gestational weight.
Conclusions: Both obesity before pregnancy and inadequate weight gain during pregnancy have a negative effect on breast-feeding practice. Women who are obese before pregnancy or who gain inadequate weight during pregnancy need extra support for breast-feeding.