Vitamin A Toxicity and Birth Defects

Women who are pregnant and take supplements containing more than two-and-a-half times the RDA for vitamin A have two-and-a-half times the risk of having a baby with defects, compared to women who don't overdose. Moreover, the women who take large amounts of vitamin A are five times more likely to have a baby with a cranial neural crest defect - or a defect resulting in a cleft palate, heart abnormalities, and brain damage. Because vitamin A is involved in the growth and development of a healthy fetus, too much A, even stored in the mother's body just before she becomes pregnant, can wreak havoc. In fact, excess vitamin A poses the most danger two weeks before conception and during the first two months of pregnancy. The RDA for pregnant women is 750-770 RE or approximately 2,500 IU. A single vitamin A supplement, and some multivitamins, can easily contain more than 10,000 IU. Prenatal vitamins contain as much as 5,000 IU per does.