The effect of particulate air pollution exposure prior to oocyte (egg) collection has on IVF outcomes is the second ground-breaking IVF research in two years released by Fertility Specialists of Western Australia (FSWA) specialists Dr Sebastian Leathersich and Professor Roger Hart.

Led by Dr Leathersich, the study was co-authored by Dr Caitlin Roche (King Edward Memorial Hospital); Dr Melanie Walls (FSWA / City Fertility); Ms Elizabeth Nathan (University of Western Australia - UWA) and Professor Roger Hart (City Fertility / UWA / King Edward Memorial Hospital).

The research was conducted over an eight-year period in Perth, Western Australia, and revealed that particulate air pollution in the weeks and months prior to oocyte (egg) collection is independently associated with reduced odds of live birth in subsequent frozen embryo transfers.


Ambient air pollution is increasing, and exposure is associated with adverse reproductive health outcomes, including infertility, miscarriage, preterm birth, and low birth weight. Animal studies have shown that air pollutants can impair sperm and egg development, ovarian reserve (egg count), and embryo development.

There is also evidence in humans that increased exposure to air pollution has a negative effect on pregnancy rates and pregnancy outcomes, but whether this is due to an effect on egg development or on early pregnancy has remained uncertain.


The research analysed 3,659 frozen embryo transfers between January 2013 and December 2021. The median female age was 34.5 years at the time of egg collection and 36.1 years at the time of frozen embryo transfer.

The study examined air pollutant concentrations over four exposure periods prior to oocyte retrieval (24 hours, 2 weeks, 4 weeks, and 3 months), with models created to account for co-exposures.

Dr Leathersich said: “This is the first study that has used frozen embryo transfer cycles to separate the effects of pollutant exposure during the development of egg cells and during the period around the time of embryo transfer and early pregnancy. We could therefore pinpoint whether pollution impacted the eggs themselves or just the early pregnancy stage.

“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 considered.”

This groundbreaking research was presented at this year’s annual European Society of Human Reproduction and Embryology’s (ESHRE) 40th Annual Meeting in Amsterdam on 8 July 2024.

It is the second global study led by Dr Leathersich, following the release of his paper on ‘Embryo retrieval in summer raising the odds of IVF success’.

Once again, congratulations to Dr Leathersich, Prof Hart, and the research team.


Fertility is a very personal thing. Individuals and couples put trust in the expertise of embryologists and specialists in the hope of having a family.

Oftentimes they may feel anxious about fertility treatment as it is a foreign and new process to them. As fertility specialists, it is our job to ensure we support them, with the highest quality care and assurance.

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