Postpartum weight loss and infant feeding

Women are often advised that lactation accelerates loss of the excess weight gained during pregnancy, but the evidence underlying this advice is sparse and conflicting. To help fill this gap, we assessed differences in the rate of postpartum weight loss in the first 9 months postpartum according to method of infant feeding.

Two hundred thirty-six women attending two public health clinics in Montreal were weighed in one to four routine infant immunization visits up to the 9th postpartum month. After each weighing, we administered a telephone questionnaire assessing the method of infant feeding (predominantly breast-feeding, mixed-feeding, or predominantly bottle-feeding) and potential confounders. Data were analyzed using unbalanced multivariate repeated measures linear regression.

Infant feeding was not associated with statistically significant differences in the rate of weight loss. Gestational weight gain, postpartum smoking, and maternal birthplace were important predictors of postpartum weight change.

Although our results cannot exclude an effect of more exclusive or more prolonged breast-feeding, breast-feeding as commonly practiced does not appear to influence the rate of postpartum weight loss. This information should be useful in counseling new or prospective mothers and in avoiding unrealistic expectations.