Unraveled connection between vitamin D and contraception discovered
Breaking Down the Link between Estrogen-Based Contraceptives and Vitamin D
In an intriguing study, researchers discovered that women who are using estrogen-based contraceptives often have higher levels of circulating vitamin D. Conversely, when these women stop using these birth control methods, their vitamin D levels plunge significantly.
This essential nutrient plays a vital role in keeping the correct levels of calcium and phosphorus in the blood. It aids the body in absorbing calcium, a fundamental component of bones. Interestingly, foods like fish and eggs are rich in vitamin D, but an overwhelming 90% of it is produced naturally in the skin due to sunlight exposure.
Deficiencies in vitamin D can lead to health issues like rickets and osteomalacia (softening of the bones). Given its importance in bone formation, it's particularly crucial during pregnancy, a time when there's an increased risk of vitamin D deficiency due to the rise in active vitamin D production to support the growth of the fetal skeleton.
Researchers from the National Institutes of Health's National Institute of Environmental Health Sciences in Research Triangle Park, NC, decided to delve deeper into any links between vitamin D levels and 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 reproductive health investigation focusing on nearly 1,700 African-American women aged 23-34 from Detroit, MI. The study questioned women about their contraceptive use, time spent outdoors, and any vitamin D supplements they consumed.
Ultimately, 1,662 women provided blood samples to measure the most common circulating form of vitamin D, known as 25-hydroxy vitamin D.
"Our study found that women who were using contraception containing estrogen tended to have higher vitamin D levels than other women," commented Dr. Quaker E. Harmon.
Even after controlling for confounding factors, such as seasonal exposure to light, the effect remained significant. According to Dr. Harmon, the team "could not find any behavioral differences such as increased time spent outdoors to explain the increase." The findings imply that contraceptives containing estrogen tend to boost vitamin D levels, and these 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 associated with an approximately 20 percent higher level of 25-hydroxy vitamin D. At the same time, current users of birth control had higher vitamin D levels, while past users had average vitamin D levels.
Vitamin D Deficiency in Early Pregnancy
This research, published recently in the Journal of Clinical Endocrinology & Metabolism, highlights the risk that women may become deficient in vitamin D as they try to become pregnant. Dr. Harmon advises that women who are planning to stop using birth control should take steps to ensure adequate vitamin D levels while attempting conception and during pregnancy.
Medical News Today asked Dr. Harmon about the possible reasons for estrogen-based contraception's effects on vitamin D levels, and she responded:
"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 study focused solely on African-American women. Medical News Today questioned Dr. Harmon about the role of race in these findings, and she 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 impactful."
Dr. Harmon is continuing to follow the women in this study to explore the relationship further. She is also working on another group of participants to investigate how vitamin D varies across the menstrual cycle.
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- The intriguing study on the link between estrogen-based contraceptives and vitamin D revealed that these contraceptives may boost vitamin D levels in women.
- Interestingly, women who stop using estrogen-based contraceptives often experience a significant drop in their vitamin D levels.
- Vitamin D plays a crucial role in maintaining the correct levels of calcium and phosphorus in the blood, aiding in the absorption of calcium, a key component of bones.
- Given the importance of vitamin D in bone formation, particularly during pregnancy, women planning to stop using birth control should ensure adequate vitamin D levels while attempting conception and during pregnancy.
- The study revealed that the use of contraceptive pills, patches, or rings containing estrogen was associated with an approximately 20 percent higher level of 25-hydroxy vitamin D, and current users of birth control had higher vitamin D levels, while past users had average vitamin D levels.
- The significant association between vitamin D levels and oral contraceptives is not limited to African-American women, as it has also been observed in young and older women who are not African-American.
