If the air around you is full of environmental chemicals, your breathing is at risk. But that’s not the only problem you should consider: A recent study found that in addition to causing increased risk of cancer and cardiovascular disorders, air pollution can also affect women’s fertility.
The new study, which was presented this month at the annual meeting of the European Society of Human Reproduction and Embryology, is based on hormone measurements from more than 1,300 Italian women. Researchers took measurements of these women’s anti-Müllerian hormone level measurements for 10 years.
The anti-Müllerian hormone (AMH) is a protein secreted by the follicular cells of the ovaries, and a person’s AMH level is often used as a proxy for the number of resting follicles in their ovaries. That number of resting follicles is referred to as the “ovarian reserve” and reflects a woman’s fertility. As such, past studies have shown that high AMH levels are correlated with age, such that levels tend to decline as women get older, especially after age 25. Smoking has also been shown to reduce AMH levels. That aligns with what we know about fertility—women become less fertile with age and when they smoke regularly.
The researchers combined the women’s AMH data with environmental data from each participant’s geographic location. Environmentally, this included looking at things like daily particulate matter (PM) in that area and levels of nitrogen dioxide in the air (a polluting gas that appears in the air when we burn fuel).
After 10 years of data collection, the researchers found the ovarian reserve was negatively affected by high levels of air pollution. That is, the women’s AMH levels decreased—and thus their fertility—when pollution levels increased. The presence of nitrogen dioxide, PM10 particles (which measure 10 micrometers or less in diameter), and PM2.5 particles (which measure 2.5 micrometers or less in diameter) was specifically correlated with reduced fertility.
“Living in an area associated with high levels of air pollutants in our study increased the risk of severely reduced ovarian reserve by a factor of two or three,” Antonio La Marca, M.D., Ph.D., lead study author and obstetrics-gynecology professor at the University of Modena and Reggio Emilia in Italy, said in a news release.
Past research has also shown air pollution may also decrease sperm quality, make fertility treatments more likely to fail, and increase the risk of miscarriage and stillbirths in those who do manage to get pregnant.
If you live in an area that might be affected by air pollution, consider checking pollution levels in your area (you can do that here; the American Lung Association recommends checking this every day) and reduce your exposure to unhealthy air on days when pollutant levels are particularly high. Per the ALA’s recommendations, it might be worth choosing to exercise indoors and avoiding exercise along major roadways, among other things, on the dirtiest air days if you’re planning to try to get pregnant any time soon.
There are other lifestyle changes you can make to increase your fertility naturally, of course, but this research suggests avoiding environmental toxins should be a priority.