A new study, exploring the effects of air pollution on women’s reproductive system, has revealed that exposure to high levels of particulate matter and nitrogen dioxide increases the risk of having a severely reduced ovarian reserve — that is, the number of viable eggs in a woman’s ovaries — “by a factor between two and three.”
The impetus to undertake the study arose from growing research indicating the negative effects of environmental chemicals and everyday diet on the physiological activity of hormones. The hormone in question is the anti- Müllerian hormone, or AMH, which is secreted by cells in the ovary and is now recognized as a reliable marker of the health of the ovarian reserve. It is known that AMH levels tend to fluctuate depending on smoking habits,body weight, long-term hormonal contraception, age, and genetics, “but a clear effect of environmental factors on the hormone has not been demonstrated [until now],” said study’s lead researcher, Antonio La Marca, of the University of Modena and Reggio Emilia, in a press release.
Titled “Ovarian Reserve and Exposure to Environmental Pollutants,” the study used real-world data of hormone measurements, taken from more than 1,300 women in Modena in northern Italy between 2007 and 2017.
La Marca and his colleagues then combined this data with daily levels of particulate matter, known as PM2.5s and PM10s, as well as levels of nitrogen dioxide, from around the participants’ home addresses. After taking into account that AMH levels generally decreased in women over the age of 25, the study found lower AMH levels among women living in areas with higher air pollution.
Specifically, women living in areas with the worst pollution levels were two or three times more likely to have AMH levels reflecting “severe ovarian reserve reduction.”
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However, the study does not pointedly address the link between air pollution and fertility. Speaking to The Guardian, La Marca said the link between AMH levels and the chances of getting pregnant naturally remains unclear; higher AMH levels simply imply a longer reproductive lifespan, making it significant also for those undergoing IVF treatments. “If you have a high AMH, you will have a higher number of eggs after ovulatory stimulation, which turns into a higher number of embryos,” he said.
It is also unclear if the negative effect of air pollution on AMH levels is temporary — that is, if a woman could raise her levels of AMH by reducing exposure to pollutants — or permanent.
While the effects of air pollution on sperm count and quality have been studied in great detail, little is known about the possible effects on women’s fertility. We know that air pollution is linked to irregular menstrual cycles in teens and that ozone air pollution could harm women’s ability to conceive (at least, in mice), but this study is the first one to directly look at the impact on the number of viable eggs in women’s ovaries… and it isn’t the best news.
This study joins a host of other studies linking air pollution to premature deaths in adults and increased chances of mouth cancer, to cognitive delays in kids, to asthma in both. It’s also been linked to problems in newborns, such as premature birth, low birth weight, respiratory problems. Even happiness might be sullied by it.
