Association of antenatal vitamin B complex supplementation with neonatal vitamin B₁₂ status: evidence from a cluster randomized controlled trial

Purpose: Evidence about the effect of maternal vitamin B₁₂ supplementation on offspring's vitamin B₁₂ status is limited. The present interventional study sought to evaluate the association of antenatal vitamin B complex supplementation with neonatal vitamin B₁₂ status.

Methods: In an ongoing cluster randomized controlled trial conducted in three rural counties in northwest China, pregnant women < 20 weeks of gestation were randomized to three treatment groups: blank control, iron supplements, or vitamin B complex supplements. All women were administered folic acid supplements during the periconceptional period. In a sub-study, we collected cord blood samples of 331 participants from the control or vitamin B complex groups in the Xunyi county from January 2017 to December 2017. Plasma concentrations of folate, vitamin B₁₂, and homocysteine were measured. Linear mixed models with a random intercept for cluster were used to compare biochemical indexes between groups after controlling for covariates.

Results: Compared with newborns whose mothers were in the control group, newborns of the vitamin B complex-supplemented women had significantly higher cord plasma vitamin B₁₂ (P = 0.001) and lower homocysteine concentrations (P = 0.043). The association of antenatal vitamin B complex supplementation with cord blood vitamin B₁₂ concentrations appeared to be more pronounced among newborns with high folate status than those with low folate status (P_interaction = 0.060).

Conclusions: Maternal vitamin B complex supplementation during pregnancy was associated with better neonatal vitamin B₁₂ status in rural northwest China.