IVF success drops by almost 40% with exposure to air pollution: study – National

A new study has found that exposure to fine particulate matter, a common air pollutant, can significantly reduce the chances of successful in vitro fertilization (IVF), even in areas with good air quality.

An Australian study published Sunday in the European Society of Human Reproduction and Embryology found that exposure to pollution before egg collection during IVF can reduce the chance of a live birth by almost 40 percent.

“Climate change and pollution remain the greatest threats to human health, and human reproduction is not immune,” said Dr Sebastian Leathersich, lead author of the study and a fertility specialist based in Australia.

“We found that increased exposure to fine particulate matter pollution (PM2.5 and PM10) in the weeks and months before egg collection was associated with lower birth rates, regardless of pollution levels at the time of embryo transfer,” he told Global News in an email sent Thursday.

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Outdoor air pollution is one of the greatest environmental risks to health and is estimated to cause more than four million premature deaths each year worldwide. World Health Organization (WHO) 2022 Report Found.

According to the WHO, exposure to particulate matter is linked to a range of harmful health problems, including cardiovascular disease, respiratory diseases and cancer.

Health Canada estimates that air pollution is responsible for 15,300 premature deaths in Canada each year, while many more people are sick for days with asthma and acute respiratory symptoms as a result of pollution.

Little research has been done on air pollution and IVF, the researchers say.

“This is the first study to look specifically at frozen embryo transfer, taking into account the conditions at the time of oocyte collection and those at the time of embryo transfer,” Leathersich said.

“Given that more and more women undergoing IVF are using frozen embryo transfer, where embryos can be used months or years after egg collection, we wanted to investigate whether contamination levels around the time of egg collection or around the time of embryo transfer were more important.”

This eight-year study in Perth, Australia, looked at more than 3,600 frozen embryo transfers involving 1,836 females. The average patient age was 34.5 years old when the eggs were collected and 36.1 years old when the embryo transfer occurred.

The researchers examined air pollution levels over four time periods before collecting the eggs (24 hours, two weeks, four weeks, and three months).

The study found that patients exposed to the highest levels of air pollution in the two weeks before egg retrieval were 38 percent less likely to have a live child than patients exposed to the lowest levels of exposure.

The researchers also found that patients exposed to higher levels of air pollution in the three months prior to egg retrieval had a lower chance of having a live child.

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The negative impact of air pollution was also observed despite the excellent general air quality during the study period, with particulate matter levels exceeding WHO guidelines respectively on only 0.4 percent and 4.5 percent of study days.

WHO guidelines recommend an annual average PM2.5 concentration of five micrograms per cubic meter of air. PM2.5 refers to airborne particles that are so small that they can enter the lungs and enter the bloodstream when breathing.

“This association is independent of air quality at the time of frozen embryo transfer. These findings suggest that pollution negatively impacts egg quality, not just early pregnancy, a distinction that has not been reported previously,” Leathersich said.

Jamie Seabrook, a professor in the Department of Epidemiology and Biostatistics at Western University in London, Ontario, described the research as a crucial contribution to understanding how pollution affects maternal health.

In 2019, Seabrook helped publish a study in environmental research research into the effects of pollution on pregnancy. The study revealed that women who typically experience high levels of exposure to sulfur dioxide were 30 percent more likely to have a low birth weight baby and 20 percent more likely to have a preterm delivery, compared to women with typically low levels of exposure.

“I would say the evidence in this area is mounting,” said Seabrook, who stressed the critical importance of such research as air quality increasingly affects human health.

In Seabrooke’s study, researchers found that pollutants enter the lungs of pregnant women and then travel to the placenta. This means that increased exposure to these pollutants leads to them passing through the mother’s lungs and reaching the fetus.

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When discussing how pollution affects the IVF process, Leathersich told Global News that it is still unclear how exposure affects outcomes. The study focuses on making connections rather than investigating the underlying mechanisms, he added.

However, he also said that particulate matter can cause inflammation, damage cells and DNA, and increase oxidative stress.

“Research over the last few years has shown that there are actually pollution particles in human ovaries and developing follicles, showing that the pollution we are exposed to can go directly into the ovaries,” he said.

“We plan to evaluate this further in the coming years, with planned studies that will look directly at the effects of pollution exposure on human eggs.”

While completely avoiding pollutants is probably not possible, Leathersich did offer some tips for pregnant women or those undergoing IVF to minimize their exposure.

“This may mean staying indoors on high pollution days (or) using air filters. Ultimately, reproductive health is part of the bigger picture when it comes to pollution, and strong government and industry action is urgently needed to reduce emissions and improve health outcomes,” he said.

Seabrook echoed these sentiments and stressed the importance of keeping car windows closed during rush hour.

“During rush hour, you should always drive with the windows up … because you’re breathing that air during rush hour, when pollution levels are higher. So if you’re pregnant or trying to get pregnant, during rush hour it’s really important to (close your windows).”