Do Pregnant Women Need More Vitamin D?

The Scoop

Taking vitamin D supplements during pregnancy is not only safe for Mother and Baby, but may also prevent preterm birth and childbirth-related infection, according to new research presented May 1, 2010, before an annual meeting of the Pediatric Academic Societies. But how much vitamin D do moms-to-be need for optimal health?

In the study, a research team from Medical University of South Carolina recruited 500 women just entering the second trimester of pregnancy and split them into three groups—one group received 400 IU of vitamin D a day until delivery (the typical amount found in most prenatal vitamins), group two received 2,000 IU, and group three received a whopping 4,000 IU.

Women were checked in on monthly as researchers kept track complication rates during pregnancy, including preeclampsia, gestational diabetes, infections, and preterm labor and birth. Complication rates for preeclampsia and gestational diabetes were similar across all three groups, but when it came preterm birth and infection, women who took 4,000 IU of vitamin D had noticeably lower rates.

"The spectacular part of the study was it showed women [who took higher doses of] vitamin D had lower rates of preterm labor and preterm birth, and lower rates of infection," says Dr. Carol L. Wagner, lead author of the study and a pediatric researcher at Medical University of South Carolina.

Your Health

What's the big deal about D? It is now known that vitamin D is critically important for maternal and infant health, including bone health and immune function. And as researchers point out, other recent studies have shown that vitamin D deficiency during pregnancy is a serious public health issue. Women typically get vitamin D from foods like vitamin D-enriched milk, supplementation, and from the sun—the "sunshine vitamin" is produced in skin exposed to direct sunlight. But as Dr. Wagner points out, "Diet doesn't provide enough vitamin D, and we don't go in the sun as much as we need."

Though some women in this study took 4,000 IU of vitamin D daily, it is important to consult with your doctor about the amount of D that is right for you. Some doctors may recommend vitamin D testing to check for deficiency. For most women, the current recommended daily intake remains 400 IU of vitamin D, usually as part of a prenatal supplement. Because of so much emerging research of vitamin D and pregnancy health, the Institute of Medicine plans to revisit prenatal vitamin D intake guidelines sometime this year.