Discoveries and Data: Exposures and Risk Factors


High doses of vitamin A induce birth defects in laboratory animals. In humans, a chemically-related substance—the acne medication Accutane—causes serious birth defects in 25% of exposed fetuses. Although its role in embryonic development is not fully understood, vitamin A is active in neural crest cell migration—movement of cells that originate around the neural tube (spinal cord) and contribute to the developing heart, thymus gland and face.


Following a report that moderate doses of vitamin A—10,000 IU/day— might cause birth defects, we looked to 3 Program studies with extensive information on nutritional factors and vitamin supplements taken during pregnancy. These included over 1500 children with oral clefts, conotruncal heart defects and neural tube defects, conditions potentially influenced by vitamin A.

Mothers whose babies had these birth defects were no more likely to have taken vitamin A supplements. Even when compared to women who didn’t take any vitamins at all, those taking vitamin A were not at higher risk.

Women who take multivitamins lower their chance of having babies with many types of birth defects. We hope confusion about vitamin A does not deter women from using multivitamins, which may protect their developing babies from birth defects.