Vitamin D during pregnancy: why most women are deficient

Vitamin D deficiency is widespread in the general population and especially common in pregnant women — estimates suggest up to 40–60% of pregnant women in northern states like Michigan have insufficient levels. Vitamin D is essential for calcium absorption, immune function, and fetal bone development, and emerging research links adequate levels to lower risk of gestational diabetes, preeclampsia, and preterm birth. The current recommended intake is 600 IU daily, but many providers and researchers suggest 1,000–2,000 IU is more appropriate for women who start deficient.

The best source is sun exposure, but in Michigan's climate a supplement is almost always necessary. Ask your provider to check your levels at an early prenatal visit.