Contraceptive pill
Contraceptive pillReuters

Contraceptive pills containing oestrogen raise the levels of vitamin D in women, as compared to the tablets that don't have the hormone, says a study published in the Endocrine Society's Journal of Clinical Endocrinology & Metabolism.

The study on the reproductive health of African-American women belonging to the age group of 23 to 34 years involved 1,700 participants living in Detroit, Michigan. The women were questioned regarding their consumption of vitamin D supplements, birth control pills and the duration of sunlight exposure.

Blood samples of 1,662 women were examined to quantify the levels of 25-hydroxy vitamin D. The chemical is said to be the most apt way to measure the levels of vitamin D in the body. The researchers observed that the use of contraceptive pills, rings or patches containing oestrogen was linked with 20 percent greater levels of 25-hydroxy vitamin D.

The women who were using contraceptives including oestrogen were found to have higher vitamin D levels while other women had average levels of the vitamin present in them.

"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," Quaker E. Harmon, the first author of the study, said.

Vitamin D is really crucial for women as it helps the body in absorbing calcium, which is necessary for bone health. Sunlight aids in producing vitamin D with the help of a chemical reaction that takes place once our body is exposed to its rays.

Pregnant women are more prone to vitamin D deficiency as they require huge amounts of the vitamin for the formation of the foetus.

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

Women must include egg yolks, beef liver, fatty fish like salmon, tuna and mackerel in their diet as they are high sources of vitamin D and help in preventing calcium deficiency. These food items should be consumed by women especially when they are pregnant and planning to conceive.