A recent Lancet research evaluated the impact of maternal vitamin B12 (cyanocobalamin) supplementation on the growth and neurodevelopment of Nepalese newborns.

The study enrolled 800 pregnant women in the double-blind, community-based, placebo-controlled clinical trial aged 20.0 to 40.0 years old and who had completed a maximum of 15.0 weeks of gestation. Participants were then randomly randomized to 50.0 g of oral cyanocobalamin per day (intervention group, n=400) or a placebo (placebo group, n=400) until six months after birth.

At the start of the trial, 569 women (71.0%) had serum vitamin B12 levels less than 221.0 pmol/L. In the intervention group, 23 women failed to follow up, three declined to continue, 19 suffered miscarriages or had their pregnancy terminated medically, and 377 live babies were recorded. In the placebo group, 17 women dropped out, one refused to continue, eight women miscarried or had their pregnancy terminated surgically, and 383 live births were recorded.

Despite increases in mothers serological vitamin B12 levels, the study indicated that vitamin B12 supplementation had no effect on primary study outcomes. At one year of age, the mean length-for-age Z scores for the intervention and placebo groups were -0.570 and -0.550, respectively. The mean Bayley-III scores of vitamin B12-treated subjects were marginally higher than those of placebo-treated participants. 

Overall, the study findings support the existing WHO advice of no regular vitamin B12 administration to women throughout the prenatal period.

(Source:https://www.news-medical.net/news/20230512/An-evaluation-of-the-effect-of-maternal-vitamin-B12-supplementation-on-postpartum-infant-growth-and-neurodevelopment.aspx)