Valproic acid, a well known anticonvulsant, is being used by psychiatrists increasingly to manage bipolar and other affective disorders. Because of the demographics of the population affected by such psychiatric conditions, more women of childbearing age are likely to be exposed to this teratogenic drug. Neural tube defects (NTD) are the most common of the major anomalies associated with in utero valproic acid exposure, and are estimated to occur in 1% to 2% of exposed fetuses. Other teratogenic effects include facial dysmorphism, congenital cardiac defects, limb reduction defects and other skeletal anomalies. Prenatal diagnosis, in particular maternal serum alpha-fetoprotein screening and targeted ultrasonography, should be offered to all pregnant women exposed to valproic acid and couples need to be aware of the prenatal diagnostic options available to them. Periconceptual prophylaxis with high doses of folic acid is recommended for all women on valproic acid and counselling should also emphasize planning pregnancy to optimize folic acid supplementation. Psychiatrists should be aware of the teratogenic potential of valproic acid and know how to counsel their patients of reproductive age.