Higher Parental Vitamin B12 and Maternal Folate Levels Linked to Lower Birth Defect Prevalence

Higher periconception parental vitamin B12 levels and higher postconception maternal red blood cell (RBC) folate levels were associated with lower predicted prevalences of birth defects in a prospective cohort study from Shanghai, China. The study included 3032 couples with biomarker measurements obtained within 4 months before conception and 17,765 women tested at 4 months of gestation or earlier. In dose–response analyses, the predicted prevalence of birth defects decreased substantially as preconception maternal vitamin B12 increased, from 49.6 cases per 1000 pregnancies among women with levels below 148 pmol/L to 16.2 per 1000 among those with levels of at least 590 pmol/L; paternal vitamin B12 showed a similar but weaker pattern, decreasing from 55.5 to 24.0 cases per 1000 pregnancies. Preconception parental RBC folate showed imprecise patterns suggesting lower predicted prevalence. After conception, maternal RBC folate levels of 906 to 1131 nmol/L were associated with a lower predicted prevalence than levels below 453 nmol/L (16.5 vs. 25.7 cases per 1000 pregnancies), with little additional reduction at higher levels. Higher postconception maternal vitamin B12 levels were also associated with lower predicted prevalence, reaching 11.8 cases per 1000 pregnancies at levels of at least 590 pmol/L compared with 20.4 per 1000 at levels of 148 to 294 pmol/L. Although residual confounding cannot be excluded, these findings suggest that adequate parental vitamin B12 around conception and adequate maternal RBC folate after conception may be associated with a lower prevalence of birth defects. Source: https://www.acpjournals.org/