Remarkable association discovered between vitamin D levels and contraceptive effectiveness
Estrogen-Based Contraceptives Linked to Higher Vitamin D Levels in Women
Women using estrogen-based contraceptive methods have been found to have higher levels of circulating vitamin D, whereas those who stop taking such contraceptives may experience a significant drop in vitamin D levels, according to a study published in the Journal of Clinical Endocrinology & Metabolism.
Vitamin D plays a significant role in maintaining proper calcium and phosphorus levels in the blood, as well as aiding the body in absorbing calcium, an essential component of bones. Sources of vitamin D include foods like fish and eggs, with nearly 90 percent of it produced in the skin through a chemical reaction prompted by sunlight exposure.
A deficiency in vitamin D can lead to conditions such as rickets and osteomalacia (softening of bones). Given its importance in bone formation, vitamin D is particularly critical during pregnancy.
Dr. Quaker E. Harmon of the National Institutes of Health's National Institute of Environmental Health Sciences in Research Triangle Park, NC, led the study to investigate any changes in vitamin D levels associated with oral contraceptive use.
Using data from the Study of Environment, Lifestyle, and Fibroids—an investigation of reproductive health—the researchers analyzed information from almost 1,700 African-American women living in and around Detroit, MI, aged 23-34. The study questioned women about their contraceptive use, including the amount of time they spent outside and any vitamin D supplements they took.
In total, 1,662 women provided blood samples to determine levels of the most common circulating form of vitamin D, known as 25-hydroxy vitamin D.
The team discovered that women using contraception containing estrogen tended to have higher vitamin D levels than other women. Even when adjusting for confounding factors like seasonal sunlight exposure, the effect remained significant.
"We could not find any behavioral differences such as increased time spent outdoors to explain the increase," said Dr. Harmon. "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."
After accounting for confounding variables, the use of contraceptive pills, patches, or rings containing estrogen was associated with a 20 percent higher level of 25-hydroxy vitamin D. Concurrent users of birth control showed higher vitamin D levels, while past users had average vitamin D levels.
These findings indicate that as a woman begins to try to become pregnant, she may face the risk of becoming deficient in vitamin D. Dr. Harmon provided advice for women planning to discontinue birth control:
"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."
The research team is continuing to follow the group of women to further investigate the relationship, while Dr. Harmon is also working on another set of participants to study how vitamin D varies across the menstrual cycle.
While the specific mechanisms and whether this association varies by race are not well-documented in the current literature, the study results highlight the importance of understanding the potential interactions and factors that may influence vitamin D levels in conjunction with estrogen use. Further research is needed to fully comprehend these dynamics.
- Being on estrogen-based contraceptive methods may result in higher levels of vitamin D in women, as shown by a study in the Journal of Clinical Endocrinology & Metabolism.
- A deficiency in vitamin D can lead to various health issues, including rickets and osteomalacia, making it particularly critical during pregnancy.
- The study, led by Dr. Quaker E. Harmon, analyzed information from over 1,600 African-American women in Detroit, MI, to investigate changes in vitamin D levels associated with oral contraceptive use.
- The research found that women using contraception containing estrogen tended to have higher vitamin D levels, even when adjusting for confounding factors like seasonal sunlight exposure.
- The use of contraceptive pills, patches, or rings containing estrogen was associated with a 20 percent higher level of 25-hydroxy vitamin D, according to the study.
- For women planning to discontinue birth control, ensuring adequate vitamin D levels while trying to conceive and during pregnancy is advisable, as the study suggests they may face the risk of becoming deficient in vitamin D.
