Women not taking contraceptives have low Vitamin D: Study

A recent study reveals that women are at a higher risk of having fallen vitamin D level when they stop using birth control pills or other contraceptives containing estrogens.

Vitamin D is majorly responsible for increasing intestinal absorption of calcium, iron, magnesium, phosphate and zinc. Proper calcium levels are necessary for bone health.

The body produces vitamin D when the skin is exposed to sunlight. A smaller portion of it also comes from food, including fatty fish and milk. Further chemical changes are needed to turn it to active form.

During pregnancy, the women produce increased amount of active vitamin D to support the formation of fetal skeleton. As a result, pregnant women face an increased risk of developing vitamin D deficiency.

Quaker E. Harmon, the study's first author, said: "Our study found that women who were using contraception containing estrogen tended to have higher vitamin D levels than other women,"

"We could not find any behavioral differences such as increased time spent outdoors to explain the increase. Our findings suggest that contraceptives containing estrogen tend to boost vitamin D levels, and those levels are likely to fall when women cease using contraception," he added.

For the cross-sectional data analysis, researchers analyzed data from several studies, including one about reproductive health conducted among 1700 African-American women between the age group of 23 and 34 who lived in Detroit or the surrounding area.

As part of the study, the participants answered questions about contraceptive use as well as the amount of time they spent outdoors and the vitamin D supplements they took.

After adjusting for seasonal exposure to sunlight, the researchers found that the use of birth control pills containing estrogens was associated with a 20 percent higher vitamin D level.

While current birth control users tended to have higher levels of vitamin D in the blood, past contraceptive users had average levels of vitamin D.

"Our findings indicate women may run the risk of developing vitamin D deficiency just when they want to become pregnant. 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," said Harmon.

The study was published in the Endocrine Society's Journal of Clinical Endocrinology & Metabolism and supported by the Intramural Research Program of the NIH's National Institute of Environmental Health Sciences.