Experts Mull Vitamin D Levels for Pregnancy

June 28, 2011

A large-scale study supports the safety and bioavailability of higher vitamin D doses for pregnant women.

In a statement released last week by the American College of Obstetricians and Gynecologists (ACOG), the group said that vitamin D screening is not necessary for pregnant women-unless they are at high risk of deficiency.

So what level of vitamin D is recommended for the average pregnant woman?

Vitamin D deficiency is a common concern for vegetarians, ethnic minorities with dark skin, and people with limited exposure to sunlight. For pregnant women, researchers suspect the nutrient may be involved in a host of functions, including cardiovascular, immune, and musculoskeletal functions.

According to the ACOG, the general consensus in the medical field is that 1000–2000 IU daily is safe for pregnant women who are deficiency in vitamin D. “Anything higher than this has not been studied,” said George A. Macones, MD, chair of ACOG’s committee on obstetric practice.

Still, medical organizations, including the Institute of Medicine, back supplemental vitamin D intake of up to 4000 IU daily. And doses this high have just been studied.

In a study published on Monday in the Journal of Bone and Mineral Research, researchers at the Medical University of South Carolina assigned pregnant women to vitamin D3 supplementation-400, 2000, or 4000 IU-daily from 12–16 weeks gestation until delivery. A total of 350 women completed the study.

Regardless of race, the percentage of women and newborns achieving vitamin D “sufficiency” (2000 IU) was significantly higher in the 4000 IU group compared to both other groups. When it came to African Americans reaching adequate vitamin D levels, the researchers said that 400 and 2000 IU of vitamin D were “comparatively ineffective” compared to the 4000 IU group.

Safety measures did not differ between groups and zero adverse events were reported.

The researchers concluded that, regardless of race, “These findings suggest that the current vitamin D [estimated average requirement] and [recommended daily allowance] for pregnancy women issued in 2010 by the Institute of Medicine should be raised to 4000 IU vitamin D per day...”

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