Exposure to air pollution may significantly reduce the chances of having a live baby after IVF treatment, a new study has found, raising further concerns about the health effects of toxic air on fertility.
Pollution exposure has previously been linked to increased rates of miscarriage and premature birth, and tiny soot particles have been shown to pass through the bloodstream to reach the ovaries and placenta, but new research suggests the effects of pollution begin before conception, disrupting egg development.
“We observed that women exposed to the highest levels of particulate air pollution prior to egg retrieval were more than a third less likely to have a baby after frozen embryo transfer compared to women exposed to the lowest levels of pollution,” said Dr Sebastian Lezarsich, a Perth-based fertility specialist and gynaecologist who will present the findings on Monday at the European Society for Human Reproduction and Embryology’s annual meeting in Amsterdam.
Air pollution is one of the major threats to human health, and the World Health Organization (WHO) has stated that the impact of air pollution on human health is 6.7 million deaths In 2019, tiny soot particles entered the bloodstream from the lungs and were carried to every organ in the body. Heart disease, Stomach cancer and dementiaPollution is also associated with reduced intelligence.
“Pollution is harmful to nearly every aspect of human health, so it’s not surprising to me that reproductive health is also affected,” said Leathersich. “I hope that these findings help highlight the urgency of the situation, where climate change, even at so-called safe levels, poses a serious and immediate threat to human reproductive health.”
The study analysed fertility treatments in Perth over an eight-year period, including 3,659 frozen embryo transfers from 1,836 patients, and tracked whether outcomes were linked to levels of fine particulate matter known as PM10. Live birth rates per transfer were around 28%. However, success rates varied depending on exposure to pollutants in the two weeks prior to egg retrieval. Comparing the highest and lowest quartiles of exposure, the odds of a live birth decreased by 38%.
“These findings suggest that pollution not only has a negative impact on early pregnancy but also on egg quality, a feature that has not been reported before,” said Lezarsich.
The team now plans to study cells directly to understand why the pollutants have such adverse effects: previous research has shown that tiny particles can damage DNA and cause inflammation in tissues.
Prof Jonathan Grigg, whose group from Queen Mary, University of London found evidence of air pollution particles in the placenta, said: “This research is biologically plausible as it has recently been discovered that inhaled fossil fuel particles leave the lungs and lodge in organs throughout the body. Reproductive health is added to the growing list of negative impacts of fossil fuel-derived particulate matter and should encourage policymakers to continue to reduce transport emissions.”
The scientists said the link was evident because overall air quality was good during the study period, but PM10 and PM2.5 levels exceeded WHO guidelines on just 0.4% and 4.5% of study days. Australia is one of only seven countries to meet WHO guidelines in 2023, and the study is the latest to provide evidence that even relatively low levels of pollution can be harmful.
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Professor Gita Nargund, senior consultant in the NHS and medical director of abc IVF and Create Fertility, said further research would be crucial to better understand the full impact of air pollution, which disproportionately affects people from lower socio-economic backgrounds.
“As we face a global fertility crisis, a clearer understanding of the links between environmental factors such as air pollution and reproductive health and treatment outcomes could play a key role in tackling fertility decline,” she said.
