The impact of air pollution is far reaching, contributing to premature deaths and numerous health effects such as cardiovascular and respiratory diseases. But did you know its effects start even before life begins? Researchers have discovered that exposure to air pollution can reduce the odds of live births after IVF (in vitro fertilization).

Exposure to fine particulate matter before egg retrieval (oocyte retrieval) in IVF can reduce live birth odds by around 40%, according to the results of the study presented at the ESHRE 40th Annual Meeting in Amsterdam on Sunday.

The researchers noted that the odds of a live birth decreased by 38% when comparing the highest quartile of PM10 exposure in the two weeks leading up to oocyte collection to the lowest quartile.

"This is the first study that has used frozen embryo transfer cycles to separately analyze the effects of pollutant exposure during the development of eggs and around the time of embryo transfer and early pregnancy. We could therefore evaluate whether pollution was having an effect on the eggs themselves, or on the early stages of pregnancy," Dr. Sebastian Leathersich, lead author of the study, said in a news release.

"Our results reveal a negative linear association between particulate matter exposure during the 2 weeks and 3 months prior to oocyte collection and subsequent live birth rates from those oocytes. This association is independent of the air quality at the time of frozen embryo transfer. These findings suggest that pollution negatively affects the quality of the eggs, not just the early stages of pregnancy, which is a distinction that has not been previously reported," Dr. Leathersich said.

The findings were made after the research team analyzed 3,659 frozen embryo transfers from 1,836 patients in Perth, Australia, over eight years.

During the study, the concentration of particulate matter was assessed over four exposure periods before oocyte retrieval (24 hours, 2 weeks, 4 weeks, and 3 months), with models created to account for co-exposures.

An increase in PM2.5 exposure in the three months before oocyte retrieval was found to be linked with decreased odds of live birth. Interestingly, the negative impact of air pollution was evident even when overall air quality was good, with PM10 and PM2.5 levels exceeding WHO guidelines on just 0.4% and 4.5% of the study days, respectively.

"Climate change and pollution remain the greatest threats to human health, and human reproduction is not immune to this. Even in a part of the world with exceptional air quality, where very few days exceed the internationally accepted upper limits for pollution, there is a strong negative correlation between the amount of air pollution and the live birth rate in frozen embryo transfer cycles. Minimizing pollutant exposure must be a key public health priority," Dr. Leathersich added.

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