Prevalence of Non-exclusive Breastfeeding in the Context of Vitamin D Supplementation During Pregnancy and Lactation in Bangladesh

Objectives: Vitamin D deficiency is a global health issue and may impact milk supply through modulating mammary inflammation and lipid metabolism. However, data is limited on the role of vitamin D in lactation outcomes. We aimed to examine the impact of vitamin D supplementation on exclusive breastfeeding prevalence during early infancy. Methods: This is a secondary analysis of a randomized controlled trial of maternal vitamin D supplementation in Dhaka, Bangladesh. In this study, participants received either prenatal vitamin D (4200 IU/wk, n=229; 16000 IU/wk, n=224; or 28000 IU/wk, n=221), both prenatal and postpartum vitamin D (28000 IU/wk; n=227), or placebo (n=223). The outcomes measured were exclusive compared to non-exclusive breastfeeding at 2 weeks (±1 week) and one month (4 weeksGD1 WRE2 ±1 week) of age. Exclusive breastfeeding was defined as only breastmilk fed to the infant for the past 7 days (maternal self-report). A log binomial regression was performed to calculate the relative prevalence of non-exclusive breastfeeding with vitamin D supplementation group (PR 95% CI). Results: Prevalence of exclusive breastfeeding in the entire cohort was 89% at 2 weeks and 84% at 1 month. Only prenatal 4200 IU/wk vitamin D resulted in lower prevalence of non-exclusive breastfeeding at 2 weeks (0.54 0.31, 0.93) vs. placebo. Both prenatal 4200 IU/wk vitamin D and prenatal/postpartum 28000 IU/wk vitamin D resulted in lower prevalence of non-exclusive breastfeeding at one month (Prenatal 4200 IU: 0.44 0.27, 0.70; Prenatal/Postpartum 28000 IU: 0.58 0.38, 0.89. Prevalences with other prenatal doses were not different from placebo. Results were similar when adjusting for gestational age, parity, maternal age, and birth mode (cesarean vs. vaginal). Conclusions: The prevalence of non-exclusive breastfeeding was lower in early infancy among mothers receiving vitamin D supplements during pregnancy and lactation, but results were inconsistent across supplementation dosage groups. Funding Sources: Penn State Huck Institutes of the Life Sciences - HITS grant; Penn State College of Health and Human Development.