Vitamin D's surprising connection to contraceptive methods revealed
Revised Article:
Women taking estrogen-based birth control pills might experience higher levels of circulating vitamin D, according to a study by researchers. Conversely, women ditching these contraceptives may face a noticeable drop in vitamin D levels.
Vitamin D, a vital nutrient, plays a crucial role in maintaining the correct calcium and phosphorus levels in the blood. It aids the body in absorbing calcium, which is essential for building strong bones. Foods like fish and eggs are rich sources of vitamin D, but around 90% of vitamin D is produced naturally in the skin due to sunlight exposure.
Vitamin D deficiency could lead to diseases like rickets and osteomalacia, which involve the softening of bones. Given its importance for bone growth, vitamin D is especially crucial during pregnancy.
Researchers led by Dr. Quaker E. Harmon from the National Institutes of Health's National Institute of Environmental Health Sciences looked into changes in vitamin D levels linked with taking oral contraceptives.
Vitamin D and Contraception
The team conducted a cross-sectional analysis of data from the Study of Environment, Lifestyle, and Fibroids (SELF), a study focusing on reproductive health. They collected data from nearly 1,700 African-American women aged 23-34 living in and around Detroit, MI. The study questioned women about their contraceptive use and included questions regarding sunlight exposure and vitamin D supplements.
The research included 1,662 women who provided blood samples to determine levels of the most common circulating form of vitamin D, called 25-hydroxy vitamin D.
During pregnancy, women create increased levels of the active form of vitamin D to support the growth of a fetal skeleton. As a result, pregnant women have a heightened risk of vitamin D deficiency and, consequently, an increased risk of developing bone problems.
"Our study found that women using contraception containing estrogen tended to have higher vitamin D levels than other women," explained Dr. Harmon. The effect remained significant even after accounting for factors such as seasonal light exposure. Dr. Harmon added, "We couldn't 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."
After adjusting for confounding variables, the use of contraceptive pills, patches, or rings containing estrogen was linked to a 20 percent increase in 25-hydroxy vitamin D levels. Current users of birth control had higher levels of vitamin D, while past users had average levels.
Vitamin D Deficiency in Early Pregnancy
These findings, published in the Journal of Clinical Endocrinology & Metabolism, suggest that women may become deficient in vitamin D as they attempt to conceive and during pregnancy. Dr. Harmon offered some advice: "For women 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."
Medical News Today asked Dr. Harmon why estrogen-based contraception might affect vitamin D levels, and she stated, "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."
The current study focused solely on African-American women. When asked whether race might play a role in this effect, Dr. Harmon said, "The same association has been observed in young and older women who are not African-American, so we believe this association is not related to race. In the United States, African-American women are more likely to be vitamin D-deficient, so small increases or decreases in their vitamin D concentrations may be more important."
Dr. Harmon also announced that she is continuing to follow this group of women to further investigate the relationship. Additionally, she is working on another group of participants to investigate how vitamin D varies across the menstrual cycle. Learn about research showing that higher vitamin D levels lower cancer risk.
- women using contraception containing estrogen tend to have higher vitamin D levels compared to other women, as revealed by Dr. Harmon's study.
- The increase in vitamin D levels is significant, even after accounting for factors such as seasonal light exposure.
- Pregnant women have a heightened risk of vitamin D deficiency and the associated risk of developing bone problems, given the importance of vitamin D for bone growth.
- The current study focusing on African-American women suggests that women may become deficient in vitamin D as they attempt to conceive and during pregnancy.
- For women planning to stop using birth control, ensuring adequate vitamin D levels while trying to conceive and during pregnancy is worth considering, according to Dr. Harmon.
- Further work is needed to understand why estrogen-based contraception might affect vitamin D levels, and whether race plays a role in this effect is yet to be determined.
