Vitamin B12, essential for nerve function, red blood cell production, and DNA synthesis, is found in animal-based foods such as poultry, meat, fish, and dairy products. A recent study from Fudan University in China reveals that sufficient vitamin B12 levels in both mothers and fathers prior to conception are associated with a significantly lower risk of birth defects.
The research, published in the Annals of Internal Medicine, analyzed data from over 3,000 couples who provided blood samples before conception, along with 17,765 women tested during early pregnancy. Researchers measured vitamin B12 and folate (B9) levels and correlated them with birth defects, including live births, stillbirths, and pregnancies ending due to fetal abnormalities.
For mothers, the risk of birth defects decreased steadily as vitamin B12 levels increased. In fathers, the risk similarly declined with higher levels initially but plateaued at moderate concentrations. These findings underscore the critical role of both partners’ nutrition before conception and during early pregnancy, expanding on previous research that primarily highlighted maternal factors.
The study found that the predicted prevalence of birth defects dropped from 49.6 to 16.2 cases per 1,000 pregnancies in mothers with the highest versus lowest B12 levels, with a comparable but smaller effect observed in fathers. Additionally, adequate folate levels in early pregnancy were also linked to reduced birth defect risks.
Earlier studies have demonstrated long-term benefits for children whose mothers maintained sufficient B12 levels during pregnancy, including improved cognitive and developmental outcomes. A 2026 systematic review of 22 studies confirmed that adequate maternal B12 status is consistently associated with better language, memory, and cognitive performance in children.
