Abstract MP63: How Much Does Exclusive Breastfeeding to the Recommended Six Months Increase Maternal Postpartum Weight Loss in Healthy Women?

Abstract

Objective: Postpartum weight retention increases the risk of future obesity and cardiovascular disease. Although exclusive breastfeeding (EBF) has been promoted as an effective means to lose gestational weight gain, previous studies report mixed findings for the relationship between duration of EBF and maternal postpartum weight loss (PPWL). This study evaluates whether meeting the recommended 6-months of EBF is associated with greater PPWL by 6-months than a shorter duration of EBF. Methods: The Mothers and Infants LinKed for Health (MILK) study is an ongoing prospective cohort of non-diabetic, non-smoking mother-infant dyads, all of whom were exclusively breastfeeding at 1-month postpartum. Breastfeeding exclusivity was subsequently self-reported by mothers at 3 and 6-months postpartum. Maternal pre-pregnancy weight and weight at delivery were abstracted from medical records. PPWL was calculated as maternal weight measured at 1, 3 and 6-months minus maternal weight at delivery. Mixed effects linear regression models were used to test the association of duration of EBF with repeated measures of PPWL after adjustment for covariates including maternal pre-pregnancy weight, gestational weight gain, parity, physical activity and infant sex. Results: Among 315 mothers who were exclusively breastfeeding at 1-month, 93% and 75% continued EBF to 3 and 6-months, respectively. By 6-months postpartum, weight loss (least square means ± standard error) was -8.55 ± 1.31 kg among EBF to 1-month, -10.60 ± 0.82 kg among EBF to 3-months and -11.73 ± 0.37 kg among EBF to 6-months (Figure). EBF to 6-months was associated with greater PPWL by 6-months postpartum than EBF to 1 or 3-months (p<0.05) after covariate adjustment. Conclusion: EBF to 6-months postpartum was associated with greater maternal PPWL than shorter EBF durations. Interventions may promote prolonged EBF as a means of increasing maternal weight loss by 6-months postpartum, but additional research is needed to explore whether these differences persist after weaning.