What is the optimal vitamin D level for pregnant women for maternal and fetal health and how should this be supplemented in pregnancy?

There is significant literature to suggest that during pregnancy maintaining a circulating concentration of 25-hydroxyvitamin D of at least 40 ng/mL can markedly reduce the risk for preeclampsia, premature births, cesarean section births, and infant dental caries. Maintaining a concentration of at least 20 ng/mL reduces the risk for gestational diabetes. This was recently reviewed by me:

Holick, PMID 39486479

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