Infant Feeding Mode is Associated with Differences in Postpartum Weight Retention and Percent Body Fat from 2 to 16 Weeks

Abstract

IntroductionPrevalence of obesity is high among women of reproductive age. Excessive weight gain during pregnancy and postpartum weight retention (WR) are contributing factors. Differences in maternal weight retention and body composition have previously been linked to differences in infant feeding mode; whether the infant is breastfed or formula fed. We investigated differences by feeding mode and change in body weight and percent body fat (%BF) from 2 to 16 weeks postpartum.MethodsParticipants were 77 healthy women and their full‐term, normal weight infants. Data were collected prospectively at 2, 8 and 16 weeks postpartum. Mothers were categorized as either predominantly breastfeeding or formula feeding. Our primary outcomes were weight and %BF to determine whether feeding mode predicts WR from 2 to 16 weeks postpartum. Percent BF was assessed using air displacement plethysmography via BOD POD (COSMED). Covariates included race and self‐reported pre‐pregnancy weight. Descriptive statistics and the interaction between feeding mode and time were assessed using a repeated measure ANCOVA.ResultsAt 2 weeks postpartum, formula feeding mothers had significantly higher body weight and %BF compared to breastfeeding mothers. They also had higher self‐reported pre‐pregnancy weight. Formula feeding mothers had higher body weight and greater %BF. A significant feeding mode by time interaction, indicated different WR patterns of change from 2 to 16 weeks; breastfeeding mothers' weight and %BF tended to decline, while formula feeding mothers' body weight and %BF tended to increase. Chi square tests for independence revealed that 87% of breastfeeding mothers lost weight between 2 and 16 weeks compared to 54% of formula feeding mothers. Results were similar for %BF, with 74% of breastfeeding mothers losing %BF compared to 40% of formula feeding mothers.ConclusionsOverall, formula feeding mothers were heavier initially, and retained more weight and %BF from 2 to 16 weeks, and a lower percentage of formula feeding mothers lost weight and %BF during this period. In this sample, formula feeding was associated with weight retention in the postpartum period, contributing to obesity and risk of chronic metabolic diseases. Guidance is needed to promote weight loss during this early postpartum period to prevent additional weight gain and obesity.Support or Funding InformationThis research was supported by The University of Georgia's Obesity Initiative and the Office of the Vice President for Research