Higher Parental Vitamin B12 Tied to Lower Prevalence of Birth Defects

TUESDAY, Sept. 1, 2026 (HealthDay News) — Lower predicted prevalences of birth defects are seen in association with periconception parental vitamin B₁₂ and postconception maternal red blood cell (RBC) folate, according to a study published online Sept. 1 in the Annals of Internal Medicine.

Hongyan Chen, Ph.D., from the Children”s Hospital of Fudan University in Shanghai, and colleagues quantified associations of parental vitamin B₁₂ and RBC folate with offspring birth defects in a prospective cohort study. The study involved 3,032 couples (73 birth defect cases) with biomarkers sampled within four months before conception and 17,765 women (327 birth defect cases) sampled at four months of gestation or earlier.

In dose-response analyses, the researchers observed an association between higher preconception parental levels of vitamin B₁₂ and lower predicted prevalence rates of birth defects. Predicted prevalence decreased from 49.6 to 16.2 cases per 1,000 pregnancies for preconception maternal vitamin B₁₂ from the lowest to highest categories (<148 to ≥590 pmol/L); a similar but attenuated pattern was seen for paternal vitamin B₁₂ (55.5 to 24.0 cases per 1,000 pregnancies). Imprecise patterns of lower predicted prevalence were seen for preconception parental RBC folate; predicted prevalence was lower at levels of 906 to 1,131 nmol/L than at levels below 453 nmol/L for postconception maternal RBC folate. Predicted prevalence was lower at higher levels of postconception maternal vitamin B₁₂.

“These findings extend work focused primarily on maternal folate and suggest that broader consideration of periconception nutritional status, including paternal vitamin B₁₂, may inform birth defect prevention,” the authors write.

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