Vitamin D deficiency in pregnancy has been associated with abnormal bone development in the fetus, newborn rickets, and fractures in the newborn.  Routine screening of Vitamin D deficiency in pregnancy is not recommended, testing in those at risk can be performed by a blood test. When Vitamin D deficiency is identified, supplementation with 1000-2000 IU/day is safe. Safety of higher doses has not been studied. In those not at risk, Vitamin D supplementation beyond that amount in a prenatal vitamin should await further studies on safety.