In summary, starting at 12 to 16 weeks of gestation, vitamin D
supplementation with 4000 IU/d was most effective in achieving
vitamin D sufficiency throughout pregnancy, 1 month prior to
delivery, and at delivery in a diverse group of women and their
neonates without increased risk of toxicity. These findings
suggest that the current vitamin D EAR and RDA for pregnant
women issued in 2010 by the IOM(62) should be raised to 4000 IU
of vitamin D per day so that all women, regardless of race, can
attain optimal nutritional and hormonal vitamin D status
throughout pregnancy.