Research shows that unhealthy air quality due to forest fires can affect fertility treatments

As wildfires rage across the West, researchers at Oregon Health & Science University have continued to investigate the effects of poor air quality on health, discovering potential impacts on reproductive outcomes, including for patients undergoing fertility treatments.

In a study published in the news Fertility and sterilityResearchers at OHSU examined the impact of unhealthy air quality resulting from the 2020 Oregon wildfires on the outcomes of patients undergoing in vitro fertilization (IVF) treatment. They found that patients exposed to bushfire smoke during the developmental phase of their treatment cycle produced fewer blastocysts, which are the multi-celled embryos that develop from a fertilized egg and can be transferred for pregnancy.

There is increasing evidence that chronic exposure to poor air quality, often due to heavy pollution or smoking, is associated with reduced reproductive outcomes. As climate change brings more severe weather, including earlier wildfire seasons, OHSU researchers wanted to better understand the effects of acute exposure at a point in time. So they looked to the wildfires of 2020, when air quality in Oregon temporarily ranked among the worst in the world and broke historic records.

“The unfortunate reality is that we are seeing more wildfires due to climate change, so I worry about how this will continue to impact not only patients undergoing fertility treatments, but all individuals trying to conceive,” says Molly Kornfield , lead author of the study. , MD, assistant professor of reproductive endocrinology and infertility at the OHSU Center for Women’s Health.

She notes that with more than 200,000 patients undergoing IVF treatment nationwide each year, this is a growing concern among reproductive health and fertility experts.

“Of course we must take broader action to slow climate change and reduce the impact and size of these fires,” Kornfield said. “But in the short term, IVF clinics can further expand the already aggressive measures they are taking to protect laboratory air quality.”

Air quality crises

The research team conducted a retrospective cohort study of 69 patients who underwent ovarian stimulation and IVF treatment during the six weeks leading up to the September 2020 Oregon wildfires, which caused unhealthy air quality for 10 days.

During a standard IVF treatment cycle, patients first receive hormone injections for one to two weeks to stimulate the ovaries and grow eggs. They then undergo an egg retrieval, and finally over the next week the eggs are fertilized by sperm and grown into blastocysts that are either frozen for later use or immediately placed into a uterus during an embryo transfer.

Researchers found that exposure to wildfire smoke during the blastocyst development phase produced fewer blastocysts during that cycle compared to the control group, whose members had no exposure to wildfire smoke. While most IVF cycles still had strong results, providers may consider delaying IVF or embryo transfers for certain high-risk patients, Kornfield said.

Kornfield noted that the Portland metro area generally has excellent air quality, and highlighted that OHSU’s fertility lab is equipped with state-of-the-art air filtration systems. OHSU providers now perform IVF procedures in a new lab space with even more optimized air filtration, including a “submarine mode” for air quality emergencies.

Researchers said higher levels of air filtration may be needed in areas more prone to wildfires, including southern, central and eastern Oregon.

“Even in a laboratory with perfect air quality, patients are still living out in the world and facing high levels of exposure to wildfire smoke,” Kornfield said. “Our hope is that this research will inform preparedness measures that can ensure the best possible outcomes for our patients when we face these serious air quality crises.”

Looking ahead, researchers will continue to evaluate the effects of air quality on reproductive outcomes, including sperm count and quality; miscarriage rates; and whether transferring embryos affected by wildfire-polluted air can affect pregnancy outcomes. Researchers are also interested in studying these effects in naturally conceived pregnancies.

“We understand the time and energy patients put into this process, and we will continue to take every measure to optimize fertility treatment outcomes,” Kornfield said. “We encourage patients to discuss any concerns with their health care team, who can provide personalized, evidence-based recommendations.”