Low levels of vitamin D linked to common vaginal infection in pregnant women

Pregnant women with low levels of vitamin D may be more likely to suffer from bacterial vaginosis (BV) – a common vaginal infection that increases a woman's risk for preterm delivery, according to a University of Pittsburgh study.

Available online and published in the June issue of the Journal of Nutrition, the study may explain why African-American women, who often lack adequate vitamin D, are three times more likely than white women to develop BV.

“Bacterial vaginosis affects nearly one in three reproductive-aged women, so there is great need to understand how it can be prevented,” said Lisa M. Bodnar, Ph.D., M.P.H., R.D., assistant professor of epidemiology, obstetrics and gynecology, University of Pittsburgh. “It is not only associated with a number of gynecologic conditions, but also may contribute to premature delivery – the leading cause of neonatal mortality – making it of particular concern to pregnant women.”

The study, which included 469 pregnant women, sought to determine whether poor vitamin D status played a role in predisposing women, especially African-Americans, to BV. Dr. Bodnar and colleagues at Magee-Womens Research Institute found that 41 percent of the study participants had BV and of these, 93 percent had insufficient levels of vitamin D. They also found that the prevalence of BV decreased as vitamin D levels rose.

Vitamin D may play a role in BV by regulating the production and function of antimicrobial molecules, which in turn may help the immune system prevent and control bacterial infection. However, only about one in four Americans gets enough vitamin D. Vitamin D deficiency may be more common in African-Americans because dark pigmentation limits the amount of vitamin D that can be made in the skin through casual exposure to sunlight. African-American women also are less likely to meet dietary recommendations of vitamin D.

“Although this is a preliminary study, it points out an interesting connection between vitamin D and BV,” said Dr. Bodnar. “We don't recommend pregnant women take mega-doses of vitamin D based on these findings, but they should talk with their doctor if they have concerns about their vitamin D status. All women should be encouraged to eat a healthy diet and take a prenatal vitamin before they become pregnant or as soon as they find out they are pregnant.”

Co-authors of the study include Marijane A. Krohn, Ph.D., and Hyagriv N. Simhan, M.D., with the University of Pittsburgh and Magee-Womens Research Institute. The study was funded by the National Institutes of Health.