Characterizing the Impact of Breastfeeding and Socioeconomic Status on Maternal Weight Change From Pregnancy to Ten Years Postpartum

Abstract

ObjectivesBreastfeeding is a potentially modifiable factor associated with less postpartum weight retention; however, in the United States women with lower socioeconomic status (SES) are less likely to initiate breastfeeding and, therefore, may be at higher risk for long-term weight retention. We sought to describe associations between duration of breastfeeding with postpartum weight retention and later BMI, and to determine whether associations varied by SES. MethodsMaternal and infant data (n = 2144 dyads) are from the Geographic Research on Wellbeing survey (GROW), a follow-up study of California’s annual statewide-representative Maternal and Infant Health Assessment. Pre-pregnancy BMI was obtained from self-report; at 4–10y postpartum, breastfeeding history and self-reported body weight were collected. Multivariable linear regression was used to examine associations between breastfeeding and long-term maternal body size. SES was calculated as a composite score of % federal poverty threshold plus education and was dichotomized. ResultsOverall, mean prepregnancy BMI was 24.9 kg/m2 while long-term weight retention 4–10 y postpartum was 4.0 kg. The sample average breastfeeding duration was 8.5 months with 61% meeting the World Health Organization (WHO) recommendations for 6 months of breastfeeding. In adjusted models, compared to women who did not meet recommendations, women who met WHO recommendations had slightly lower long-term postpartum weight retention (b = –1.06 kg, CI: –1.93, –0.25, p = 0.01) and a small reduction in BMI (b = –0.4 kg/m2 95% CI –0.74, –0.08; p = 0.02). Compared to higher SES women, fewer lower SES women ever breastfed (89% vs 74%, p < .0001) or met WHO recommendations (70% vs 51%, p < .0001). Lower SES women had higher prepregnancy BMI (25.9kg/m2 vs 23.5, p < .0001), and had greater long-term weight retention 4–10 y postpartum (5.68kg vs. 1.83, p < .0001). In SES stratified adjusted models, there were no differences in associations between breastfeeding with long-term weight retention or BMI. ConclusionsBreastfeeding was associated with long term maternal postpartum weight status. Six months of breastfeeding was associated with lower long-term postpartum weight retention and lower BMI at 4–10 years postpartum, and effects did not vary by socioeconomic status. Funding SourcesCDPH, UCSF.