A recent study which examined the danger of air pollution to the population has found that air pollution significantly increases the risk of infertility. The study was conducted in China, and analyzed over 10,000 couples. The study focused on the type of pollution which is considered to be the most harmful to human health – small particles in the air which are known to cause strokes, asthma and cancer. The results of the study now suggest that it could be partially responsible for fertility issues, finding that those living in areas with worse air quality were less likely to conceive. The study hopes to explain a recent rise in unexplained infertility.
The study was published in Environment International, entitled, Association between exposure to airborne particulate matter less than 2.5 μm and human fecundity in China. If concluded that those exposed to higher levels of this small-particle pollution were noted to have a 20% increased likelihood risk of infertility. Infertility was defined as not becoming pregnant within a year of trying. The study did not determine how air pollution caused infertility but suspected that as air pollution can cause inflammation in the body, this could damage egg and sperm production.
The research found that over a year, women who were exposed to small particle pollution 10 micrograms per cubic meter higher had a 20% greater risk of infertility. The research found a 11 percent drop in fertility for every increase of 10 micrograms of small particle air pollution. The Guardian wrote: ‘the average pollution level for the Chinese couples was 57µg/m3. In London, UK, the average is about 13µg/m3. The results also showed that the proportion of women not becoming pregnant after 12 months of trying rose from 15% to 26% when comparing the quarter exposed to the lowest pollution with the quarter suffering the highest. The researchers took account of other factors including age, weight, income, smoking, alcohol drinking, and exercise levels.’
Qin Li, lead researcher on the study at the Centre for Reproductive Medicine at Peking University Third hospital in China, said to the Guardian,
‘“Numerous studies have noted that air pollution is associated with lots of adverse pregnancy events… Approximately 30% of infertile couples have unexplained infertility,” Li and colleagues wrote, noting that age, weight and smoking were well-known factors. “[Our study] indicates that small-particle pollution could be an unignorable risk factor for infertility.”’
The study has been noted to be the first to look at the relationship between pollution and fertility in the general population. Li stating: “our study samples were recruited from the general population, so our findings may be more generalizable.” Previous studies have found a correlation between infertility and pollution as well. Between the years of 2001-2011, eight power plants were closed in California, resulting in an upswing in fertility rates. Researchers from the University of California at Berkeley came to the hypothesis that air pollution may be damaging to reproductive health. Harvard T.H. Chan School of Public Health also reported that a study conducted by research fellow Audrey Gaskins found that ‘women undergoing in vitro fertilization who lived close to major roadways had a lower chance of a successful embryo implantation and live birth than those who lived farther from major roadways and heavy traffic pollution.’
Popular Science reported at the time, Joan Casey, a postdoctoral scholar in the School of Public Health at the University of California at Berkeley stating, “There’s growing evidence that there may be a relationship between air pollution and fertility… It’s really convincing that something might be going on.”
In 2019, New Scientist also reported on a study which based its findings on measurements of the anti-Mullerian hormone (or AMH) taken from 1318 women in Modena, Italy. This hormone is released by cells in the ovary and is believed to represent the number of eggs a woman has. Antonio La Marca at the University of Modena and Reggio Emilia in Italy said: “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.”
Another recent study, which assessed 632 women attending a fertility clinic in Massachusetts found a link between air pollution and decreased fertility levels, the study, entitled, Exposure to Fine Particulate Matter and Ovarian Reserve among Women from a Fertility Clinic, concluded: ‘among women from an infertility clinic, higher PM2.5 exposure was associated with lower ovarian reserve, raising concern that air pollution may accelerate reproductive aging.’