(NewsNation) — Women undergoing fertility treatments including in vitro fertilization can face additional issues if exposed to unclean air, a study by the Oregon Health & Science University found.

The study, which analyzed the impact of the 2020 Labor Day wildfires in Oregon on 69 women undergoing IVF treatments, found the regimen less effective when the air quality was worse.

Patients exposed to wildfire smoke had fewer blastocysts, or clusters of cells formed during embryonic development, which can be placed in a uterus or frozen for future implantation. The opposite was noted for those who avoided wildfire smoke.

While it hindered blastocyst production, the air quality did not negate the treatments entirely, with a majority of patients still getting pregnant from the treatments.

Dr. Molly Kornfield, the study’s lead author and assistant professor of reproductive endocrinology and infertility at the OHSU Center for Women’s Health, told the Oregon Capital Chronicle that while pregnancies are possible, it might be a good idea to hold off if air quality is an issue.

“For particular patients, in particular situations, we may consider delaying or canceling if things can be predicted, and then advising patients to take as much precaution as possible,” Kornfield said.