Wildfire air pollution may adversely affect IVF outcomes
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ANAHEIM, Calif. — Embryos had a lower blastocyst yield when exposed to wildfire smoke during development, according to data presented here.
Exposure to wildfire smoke did not appear to affect outcomes for women undergoing ovarian stimulation.
“Chronic exposure to poor air quality is associated with worse reproductive health outcomes, including an increase in infertility, pregnancy loss and impaired fetal growth,” Molly S. Kornfield, MD, a reproductive endocrinology and infertility fellow at Oregon Health & Science University in Portland, told Healio. “Our team was interested in how this severe and acute air quality event could affect our patients undergoing fertility treatments. There is also a known negative impact of poor air quality in the IVF laboratory, and so incredible attention is paid by IVF labs, including ours, to optimize air quality.”
Kornfield and colleagues conducted a retrospective cohort study of 26 IVF cycles that occurred during the September 2020 Oregon wildfires. These wildfires caused 10 days of unhealthy air quality. The researchers evaluated the effects of poor air quality on the following groups:
- 11 cycles with patients who underwent at least 4 days of stimulation during the wildfires (termed patient exposure);
- nine cycles with embryos that underwent at least 1 day of fertilization and/or culture during the wildfires (termed embryo exposure); and
- six cycles that underwent both types of exposure.
These cycles were compared with 43 control cycles performed in the 2 months before the wildfires.
Embryos exposed to unhealthy air quality had significantly fewer blastocysts develop vs. control embryos (P = .049). These cycles also had a greater proportion of cycles in which no blastocysts developed (20% vs. 2%; P = .049).
There were no differences in IVF outcomes between patients who were and were not exposed to unhealthy air quality during the wildfires.
Comparisons between the cycles with patient exposure only, embryo exposure only and both types of exposure revealed that the combined group developed the fewest blastocysts (P = .048) and the embryo exposure only group had the most cycles in which no blastocysts developed (P = .04).
“The take-home message is that air quality matters,” Kornfield said. “In a study we presented last year, we found that sperm counts were lower following the wildfires as well. Unfortunately, wildfires appear to be increasing related to climate change. We need to take broader measures to slow climate change and reduce the impact and extent of these fires. IVF clinics will need to further increase the already aggressive measures they take to protect air quality in the lab.”
Future research should investigate whether transferring embryos affected by wildfire-polluted air affects pregnancy outcomes, Kornfield said.