US Pharm. 2016;41(9):HS-12.

Women risk having their vitamin D levels fall when they stop using birth control pills or other contraceptives containing estrogen, according to a study published in the Endocrine Society’s Journal of Clinical Endocrinology & Metabolism.

Researchers analyzed data from the Study of Environment, Lifestyle & Fibroids (SELF), a study of reproductive health in nearly 1,700 African-American women between the ages of 23 and 34 years. The women lived in the Detroit, Michigan, area. Study participants answered questions concerning contraceptive use, the amount of time they spent outdoors, and any vitamin D supplement use.

“Our findings indicate women may run the risk of developing vitamin D deficiency just when they want to become pregnant,” said the study’s first author, Quaker E. Harmon, MD, PhD, of the National Institutes of Health’s National Institute of Environmental Health Sciences in Research Triangle Park, North Carolina. Harmon said, “For women who are planning to stop using birth control, it is worth taking steps to ensure that vitamin D levels are adequate while trying to conceive and during pregnancy.”