Research Finds Link Between Birth Control And Levels Of Vitamin D In Women

Researchers have found that women who take estrogen-based contraceptives also intake higher quantities of vitamin D, and conversely, that those who discontinue their use of birth control face a significant drop in levels of Vitamin D.

In addition to helping the body absorb calcium, an essential component of bones, vitamin D has the important job of maintaining the correct levels of phosphorus and calcium in the blood.

Though 90 percent of vitamin D is produced through the skin as the result of a chemical reaction caused by exposure to sunlight, deficiency may cause rickets and bone softening – a condition known as osteomalacia.

Vitamin D is vital in the formation of bones, making it particularly important during pregnancy.

Researchers who conducted a recently NCBI published study, led by Dr. Quaker E. Harmon, of the National Institutes of Health’s National Institute of Environmental Health Sciences in Research Triangle Park, NC, tested links between this vital nutrient and oral birth control pills.

The researchers executed a cross-sectional analysis of data from the Study of Environment, Lifestyle, and Fibroids (SELF), an investigation of reproductive health. Almost 1,700 African-American women aged 23-34 who live in and near Detroit, MI were involved.

Researchers surveyed women’s responses to a series of questions including time spent in the sunlight, and any vitamin supplements they may have taken.

1662 women gave blood samples to be analyzed for Vitamin D levels, as delivered by the most common form in this demographic area, known as 25-hydroxy vitamin D.

“We do not know why vitamin D levels are higher. Other work suggests that the levels of other vitamin D metabolites are changed when women use estrogen-containing contraception. This suggests that there may be alterations in the metabolism of vitamin D. Further work is needed.” explains lead study author Dr. Quaker E. Harmon.

Harmon went on to add that they observed similar association in women of different demographics, leading them to believe that the link is not related to race. He does, however, note that because African American Women are more likely to be vitamin D deficient, small increases or decreases in vitamin D levels may be more important for these individuals.

Women produce higher levels of vitamin D during pregnancy to support the growth of the fetal skeleton. As a result of this, pregnant women have a heightened risk of vitamin D deficiency and, thus, a higher risk of developing bone problems.