(P17-065-23) The Effects of Prenatal and Postnatal Maternal High-Dose Vitamin B-12 Supplementation on Human Milk Vitamin B-12 in Tanzania

Objectives: Vitamin B-12 status in human milk (HM) has critical implications for infant growth and development. This research aimed to assess the effects of prenatal and postnatal vitamin B-12 supplementation on HM vitamin B-12 at six weeks and seven months postpartum.

Methods: Data from a randomized, double-blind, placebo-controlled trial of maternal multiple micronutrient supplementation in Tanzania were used. HIV-negative pregnant women were enrolled in antenatal clinics in Dar es Salaam, Tanzania, between 2001 and 2004. From recruitment (during 12 to 27 weeks of gestation) through 6 weeks postpartum, participants were randomized to receive daily oral multiple micronutrient supplementation or a placebo. From 6 weeks to 18 months postpartum, a subset of participants was randomized to postnatal supplement or placebo. The supplement included 50 μg/d of vitamin B-12 and various other vitamins. HM vitamin B-12 concentrations were analyzed at six weeks (n = 877) and seven months (n = 444) postpartum. Linear and log-binomial models were used to examine the effects of prenatal and postnatal vitamin B-12 supplementation on HM vitamin B-12.

Results: The prevalence of HM vitamin B-12 of less than 310 pmol/L was 71.6% and 68.2% at six weeks and seven months postpartum, respectively. Prenatal supplementation significantly increased HM vitamin B-12 concentration (adjusted percent difference: 20.1; 95% CI: 9.72, 31.5; P < 0.001) and reduced the risk of HM vitamin B-12 of less than 310 pmol/L (adjusted RR: 0.83; 95% CI: 0.75, 0.91; P < 0.001) at six weeks postpartum; this effect was no longer significant at seven months postpartum. Postnatal supplementation significantly increased HM vitamin B-12 concentration (adjusted percent difference: 15.5; 95% CI: 1.66, 31.3; P = 0.027) and reduced the risk of HM vitamin B-12 of less than 310 pmol/L (adjusted RR: 0.83; 95% CI: 0.73, 0.95; P = 0.009) at seven months postpartum.

Conclusions: Continued supplementation from pregnancy through lactation may be important to the sustained status of vitamin B-12 in populations with low dietary intake of vitamin B-12.

Funding Sources: This research was supported by the Early Career Award from the Thrasher Research Fund.