Air pollution found to risk chances of live birth from IVF

New Delhi: Air pollution could lower the chances of a live birth from in vitro fertilisation (IVF) by nearly 40 per cent even in areas with "excellent" air quality, a study has found.

IVF involves fertilising a mature egg with a sperm in a lab to form an embryo, which is then placed in a uterus to develop into a baby.

In this study, over an eight-year period, researchers analysed close to 3,660 frozen embryo transfers (an IVF procedure) from 1,836 patients in Perth, Australia. During the transfer process, frozen embryos are thawed and placed in a woman's uterus.

The researchers, including those from the Perth Children's Hospital, looked at air pollutant levels over four lengths of duration - 24 hours, two weeks, four weeks, and three months - prior to oocyte retrieval, which is when eggs are taken from the women's ovaries before being fertilised with a sperm.

A higher exposure to fine particulate matter (PM10) in the two weeks leading up to oocyte collection was found to cut down the successful birth rate of an IVF by 38 per cent.

Increasing exposure to PM2.5 in the three months prior to oocyte collection was also related to lowered chances of live birth, the researchers found. The findings were presented at the 40th Annual Meeting of the European Society of Human Reproduction and Embryology (ESHRE) in Amsterdam.

"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," said lead author Sebastian Leathersich, a specialist obstetrician and gynaecologist, Perth Children's Hospital.

The negative impacts of air pollution were observed despite excellent air quality prevailing during the study period, with PM10 and PM2.5 levels exceeding the World Health Organization's guidelines on only 0.4 per cent and 4.5 per cent of the study days, respectively, the researchers stressed.

"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," said Leathersich.

Human reproduction is not immune to pollution and climate change, the greatest threats to human health, said Leathersich.

"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. Minimising pollutant exposure must be a key public health priority," said Leathersich.

The study appears as an abstract in the journal Human Reproduction.