Data published in BMJ Paediatrics Open indicated that maternal supplementation of 250 micrograms per day of vitamin B12 for approximately 17 months led to significantly higher mental developmental quotients (DQs) in the infants, compared to mothers who only received 50 micrograms per day for the same period.
“Most research on B12 supplementation in pregnancy is observational, though some recent RCTs add to the evidence,” wrote researchers from India, Nepal and the UK. “While B12 supplements appear beneficial—especially for those with deficiencies—the evidence base is debated for public health recommendations.
“Our study stresses the need for guidelines on B12 for vegetarian pregnant women. Routine supplementation (500–1500 µg) is typically limited to those with private healthcare, as national programs do not include it. With vegetarianism rising, especially in cities, clear expert guidance is urgently needed.”
B12
B12 supplementation is a common approach to maintaining adequate circulatory levels in individuals at risk of deficiency, such as vegans, older people and those with digestive disorders.
Before and during pregnancy, adequate intake of vitamin B12 is critical for both maternal metabolism and healthy brain and nervous system development in the child.
The new study, which is called MATCOBIND (Maternal B12 Supplementation to Improve Infant B12 Status), was performed at two major maternity care centers in India and Nepal. Five hundred and thirty-one vegetarian mothers completed the study.
Study details
Starting in the first trimester, the women were randomly assigned to received either 50 µg or 250 µg of vitamin B12 (methylcobalamin) every day until six month post-partum.
“The higher dose, 250 µg, was chosen based on earlier evidence of its ability to improve maternal B12 levels during pregnancy,” the researchers explained. “We did not use a true placebo, as prior research has shown that withholding B12 can cause maternal levels to decline, raising ethical concerns. Instead, the 50 µg/day group served as a lower-dose comparator to prevent deficiency rather than act as a biological ‘null’. This dosage has previously been shown to maintain maternal B12 status in pregnant women in India.”
Infant mental development, which was assessed at 9 and 12 months of age using the Developmental Assessment Scales for Indian Infants, was found to be two developmental quotient points higher in the high-dose B12 group, compared to the lower dose group.
On the other hand, no differences between the groups were observed for motor development quotients.
The researchers called for longer-term studies, more detailed developmental assessments and neuroimaging techniques to further explore the potential benefits of B12 supplementation on infant brain development.
Source: BMJ Paediatrics Open. 2026;10:e004112. doi: 10.1136/bmjpo-2025-004112. “Maternal supplementation of vitamin B12 in predominantly vegetarian pregnant women improves their vitamin B12 status and the neurodevelopment of their infants: the MATCOBIND multicentric double-blind randomised control trial”. Authors: J. Nagpal, et al.
