A prospective cohort study has found that higher parental vitamin B12 before conception and higher maternal RBC folate concentrations after conception may be associated with lower birth defect risk. The findings, published in Annals of Internal Medicine, suggest the nutritional status of both parents around conception could play a role in preventing birth defects.

A research team from the Children’s Hospital of Fudan University and colleagues used the Shanghai Preconception Cohort to study 3,032 couples, who provided blood samples within four months before conception. A total of 17,765 women were tested at four months’ gestation or earlier.

Researchers measured vitamin B12 and folate levels, then examined their relationship with birth defects identified among live births, stillbirths and pregnancies ending because of fetal abnormalities.

They found higher preconception maternal and paternal vitamin B12 levels were associated with lower predicted prevalence of birth defects. Additionally, mothers with adequate RBC folate levels in early pregnancy had lower predicted prevalence of birth defects.