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“This important study highlights a significant link between air pollution and lower IVF success rates, with a notable reduction in live births associated with higher particulate matter exposure before oocyte retrieval. These findings emphasise the need for ongoing attention to environmental factors in reproductive health.”

                -Prof Anis Feki, Chair of European Society of Human Reproduction and Embryology

A study that was submitted and presented at the ESHRE’s 40th Annual meeting has implied that particulate matter exposure before the oocyte retrieval during IVF, corresponded to a reduction in live births by about 40%. The study was published in Human Reproduction. On comparing the highest quartile of exposure against the lowest quartile of exposure to the particulate matter, it was observed that the odds of a live birth decreased by 38%. This study was conducted for eight years in Perth, Australia. The researchers analysed 3,659 frozen embryo transfers from the cohort of 1,836 patients. The median age for females at the oocyte retrieval time was 34.5 years and at the time of frozen embryo transfer was 36.1 years. The air pollutant concentrations were examined over four exposure periods prior to the oocyte retrieval which was for 24 hours, 2 weeks, 4 weeks and three months. Models were also made to take into consideration the co-exposures. The ever so increasing PM2.5 exposure was associated with decreased odds of live birth in the three months prior to oocyte retrieval, in the second quartile; the levels fell from 0.90 to 0.66 in the forth quartile.

The negative impact of the air pollution was fundamentally observable even though there was prevalence of an overall excellent air quality while the study took place. The PM10 and PM2.5 levels had drastically exceeded the WHO guidelines of 0.4% and 4.5%. Dr Sebastian Leathersich, who is the lead author of the study, explains, “This is the first study that has used frozen embryo transfer cycles to separately analyse 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. Our results reveal a negative linear association between particulate matter exposure during the two weeks and three 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.”

The epidemiological data points towards a strong link between air pollution and poor reproductive outcomes but the mechanisms remain unclear. He further adds, “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 air pollution, there is a strong negative co-relation between the amount of air pollution and the live birth rate in frozen embryo transfer cycles. Minimising pollutant exposure must be a public health priority.”