Big effect
Pregnant women taking 250 µg/day of B12 had infants scoring 7.8 centiles higher on a mental development test — but only compared with a 50 µg dose, and the effect may not apply outside vegetarian populations.
This is one of the first rigorous trials to link prenatal B12 dose size to infant neurodevelopment, but with no placebo group and a single, specific population (vegetarian mothers), the finding is promising but far from settled.
In a double-blind trial of 276 vegetarian pregnant women, those who took 250 µg of B12 daily had babies with slightly higher mental development scores at 6 months than those who took a lower 50 µg dose. The difference — about 8 percentile points — was statistically significant, but the study didn't test against a true placebo, so it's unclear whether any B12 dose above usual intake levels drives the benefit.
Where this fits in the evidence
This is among the first studies we've indexed on Vitamin B12 for Improved Mental Developmental Quotient — treat it as an early signal until more research accumulates.
The study
- Randomized Controlled Trial (RCT)
- n = 276
- 2026-03
- BMJ paediatrics open
This is a plain-language summary of a research finding, not medical advice. Pillser surfaces research signals to help you decide what's worth investigating — always consult a qualified professional before changing what you take.