Higher-Dose Vitamin B12 in Pregnancy Linked to Boost in Infant Cognitive Scores, New Trial Finds

NEW DELHI / KATHMANDU — A landmark multicenter clinical trial conducted across India and Nepal has found that higher-dose vitamin B12 supplementation during pregnancy significantly improves early mental development in infants. The study, published March 17, 2026, in BMJ Paediatrics Open, suggests that increasing daily B12 intake for pregnant women—particularly those on vegetarian diets—could be a low-cost, high-impact intervention to enhance neurodevelopmental outcomes in regions where deficiency is endemic.

The double-blind, randomized controlled trial followed 531 mother-infant pairs from the first trimester through six months postpartum. Researchers found that infants born to mothers receiving 250 micrograms ($\mu g$) of vitamin B12 daily scored higher on cognitive assessments at 9 to 12 months of age compared to those whose mothers received the lower dose of 50 $\mu g$.

Addressing a “Hidden Hunger” in South Asia

Vitamin B12, or cobalamin, is a critical micronutrient essential for DNA synthesis, red blood cell formation, and the development of the central nervous system. Because B12 is found naturally almost exclusively in animal-sourced foods like meat, fish, eggs, and dairy, deficiency is a widespread public health challenge in South Asia.

In India and Nepal, where vegetarianism is often a lifelong cultural or economic practice, B12 deficiency affects an estimated 50% to 70% of pregnant women. Despite its known role in fetal brain development, B12 is not currently a standard component of many national antenatal supplementation programs, which typically focus on iron and folic acid.

“Vitamin B12 remains poorly addressed in routine antenatal care,” said Dr. Jitender Nagpal, lead investigator and Deputy Medical Director at the Sitaram Bhartia Institute of Science and Research in Delhi. “Optimizing Vitamin B12 intake during pregnancy could represent a simple, safe, and low-cost refinement of antenatal nutrition strategies.”

Key Findings: The Power of 250 Micrograms

The study divided participants into two groups: one receiving a “standard” supplemental dose (50 $\mu g$) and another receiving a “higher” dose (250 $\mu g$). While both groups received doses significantly higher than the World Health Organization’s (WHO) minimum recommended intake of 2.6 $\mu g$ (to account for low absorption rates in deficient populations), the higher-dose group showed markedly better outcomes:

• Deficiency Reduction: The higher-dose group experienced a 30% relative reduction in biochemical B12 deficiency compared to the lower-dose arm.

• Cognitive Gains: At 9 to 12 months, infants were assessed using the Bayley Scales of Infant and Toddler Development (BSID). Infants in the 250 $\mu g$ group scored approximately 2 developmental quotient (DQ) points higher in mental development.

• Motor Function: Interestingly, motor development scores remained similar between the two groups, suggesting the benefits were specifically concentrated in cognitive processing and neuro-signaling.

The Biological Connection: Myelination and Brain Health

The brain undergoes rapid growth during the second and third trimesters of pregnancy. Vitamin B12 plays a foundational role in myelination—the process of forming a fatty sheath around nerve fibers that allows electrical impulses to transmit quickly and efficiently.

Think of B12 as the insulation on a copper wire. Without adequate insulation, the signal becomes “leaky” or slow. By ensuring the mother has sufficient B12 levels, the fetus can effectively “wire” its brain for future learning and sensory processing.

Expert Perspectives and Context

While the 2-point increase in DQ scores may seem modest on an individual level, public health experts argue that such gains are significant when applied to an entire population.

“Even small gains in early cognitive development can translate into substantial population-level benefits in learning potential,” Dr. Nagpal noted.

However, some experts urge a cautious interpretation of the data. Dr. Ram K. Chandyo, who was involved in previous trials in Nepal, pointed to a 2023 Lancet study where a 50 $\mu g$ dose improved B12 status but did not result in measurable growth or neurodevelopmental changes. This suggests there may be a “threshold effect” where only higher doses can overcome chronic, deep-seated deficiencies to actually move the needle on brain function.

A pediatric nutritionist not involved in the trial added, “While these results are promising for deficient vegetarians, we still need to track these children as they age to see if these 12-month gains lead to better school performance or higher IQ in later childhood.”

Limitations and Counterarguments

The study was specifically designed for vegetarian women in South Asia, meaning the results may not be directly generalizable to omnivorous populations or those in Western countries where B12 fortification in cereals and flour is more common.

Additionally, the trial’s modest effect size highlights the complexity of neurodevelopment. Factors such as maternal stimulation, breastfeeding duration, and other micronutrients (like Omega-3 fatty acids and iodine) also play vital roles. Critics also point out that while the trial showed safety, larger-scale longitudinal studies are required before national health ministries officially change clinical guidelines.

What This Means for Expectant Mothers

For health-conscious consumers, especially those following plant-based diets, the study offers actionable insights:

1. Screening is Key: Pregnant women should consider asking their healthcare provider for a B12 blood test (serum B12 or methylmalonic acid) early in the first trimester.

2. Dietary Sources: If the diet allows, incorporating dairy and eggs can help, though supplementation is often necessary for strict vegetarians.

3. Consult Professionals: While the 250 $\mu g$ dose showed benefits in this specific study, individuals should never self-prescribe high-dose vitamins. Excessive intake of certain nutrients can sometimes mask other deficiencies, such as folate.

The Road Ahead: Policy and Human Capital

In nations like India and Nepal, scaling a higher-dose B12 program could cost mere pennies per dose. If further research confirms these cognitive gains are sustained, B12 could join iron and folic acid as a “triple threat” against preventable developmental delays. For now, the medical community views this trial as a major step toward closing the “nutrition equity” gap between high-resource and low-resource settings.

Medical Disclaimer: This article is for informational purposes only and should not be considered medical advice. Always consult with qualified healthcare professionals before making any health-related decisions or changes to your treatment plan. The information presented here is based on current research and expert opinions, which may evolve as new evidence emerges.

References

• NDTV Health. “Higher-Dose Vitamin B12 In Pregnancy Improves Early Cognitive Development In Babies.” March 27, 2026.