Wildfire smoke contains a mixture of harmful pollutants, including particulate matter (PM2.5), volatile organic compounds (VOCs), and other toxic substances. These pollutants can have a significant impact on air quality and human health. While research on the specific effects of wildfire smoke on in vitro fertilization (IVF) outcomes is limited, there are several potential ways in which exposure to wildfire smoke could affect IVF success rates and pregnancy outcomes:
Systemic Inflammation: Wildfire smoke exposure has been linked to increased inflammation throughout the body due to the release of inflammatory cytokines. Chronic inflammation can disrupt the delicate hormonal balance necessary for successful implantation and pregnancy maintenance.
Oxidative Stress: The pollutants in wildfire smoke generate oxidative stress in the body, causing an imbalance between free radicals and antioxidants. Oxidative stress can damage reproductive cells, affecting egg quality, sperm function, and embryo development.
Endometrial Receptivity: Exposure to pollutants from wildfire smoke may alter the receptivity of the uterine lining (endometrium), making it less favourable for embryo implantation.
Hormonal Disruption: Wildfire smoke contains compounds that can mimic or interfere with hormones in the body (endocrine-disrupting chemicals). Hormonal disruption can lead to irregular menstrual cycles and affect the timing of ovulation, potentially reducing the chances of successful IVF.
Blood Flow and Oxygen Delivery: Pollutants in wildfire smoke can impact blood vessel function and reduce oxygen delivery to tissues, including the uterus. This can negatively affect the development of the embryo and its attachment to the uterine wall.
Stress and Mental Health: Wildfires and their associated smoke can cause significant stress and anxiety. High levels of stress and mental health issues have been shown to influence fertility and IVF success rates.
There are a few areas where we do have insight into the direct impacts of wildfire smoke exposure and fertility and/or pregnancy outcomes:
Sperm Health - Semen quality is significantly poorer in the three months following the sudden onset of hazardous air quality from wildfires.
IVF Outcomes - A very small clinical study showed that embryos exposed to unhealthy air quality had significantly fewer blastocysts developed vs. control embryos (P = .049). These cycles also had a greater proportion of cycles in which no blastocysts developed.
Pregnancy Outcomes - Exposure (as little as one day) in the second trimester of pregnancy may increase the risk of preterm birth and lower birth weight
What to do? Limit time outdoors, consider wearing an N95 respirator face mask, use high-quality indoor air filters during wildfire events.