Excessive intake (hypervitaminosis) of which of the following vitamin is associated with increased risk of congenital malformations:

Ans. is 'a' i.e. Vitamin ARef.: K.D.T. 5th/e, p818, Ghai, 5th/e, p79 RepeatGhai writes - "There are limited human data that directly link teratogenicity in women exposed early in pregnancy to high doses of preformed vitamin A, i.e. retinol and retinyl esters. However, teratogenic effects from naturally occuring metabolites of vitamin A e.g. trans-retinoic acid and 13 cis retinoic acid are well documented within first six weeks of pregnancy. Severe congenital malformations may occur in infants of mothers consuming large amounts of oral retinoids for treating acne."