News | Seasonal Air Pollution Adversely Affects IVF Success Rates
A recent study published in BMC Public Health examined how seasonal fluctuations in fine particulate matter (PM2.5) pollution affect assisted reproductive technology (ART) outcomes. A sharp winter increase in PM2.5 pollution was closely associated with lower in vitro fertilization (IVF) success rates, adding to concerns about the potential impact of environmental pollution on fertility.
How Does Air Pollution Affect Fertility?
Assisted reproductive technology success is affected by age, lifestyle, genetics, and other factors. The effects of PM2.5 exposure on reproductive health, particularly ART outcomes, remain unclear.
Long-term exposure to PM2.5 air pollution significantly increases the risk of cardiovascular and respiratory disease. Existing evidence suggests that air pollution may also reduce fertility and increase pregnancy complications, particularly by lowering live birth rates. Clinicians therefore often recommend reducing air pollution exposure for at least three months before beginning IVF treatment.
Despite these observations, research on the effects of seasonal PM2.5 levels on ART outcomes remains limited.
Study Background
The study was conducted by Shangqiu First People’s Hospital and included 13,476 patients with infertility who received ART treatment between February 2018 and December 2022. About 4,000 patients were treated in spring and summer, compared with 2,300 in winter and 3,400 in autumn.
Researchers focused on PM2.5 exposure during the critical period from the start of controlled ovarian stimulation to 30 days after pregnancy testing, when optimal egg and embryo development and implantation are particularly important.
Study Findings
With the same ovarian stimulation medications used, several fertility measures across all seasons were associated with PM2.5 exposure. These included early-stage ART measures such as the number of eggs, the number of eggs reaching the second meiotic metaphase (MII), the number of transferable embryos, and the number of high-quality embryos.
After adjustment for age and expected seasonal variation, PM2.5 exposure was significantly negatively associated with pregnancy and live birth rates but had no significant effect on miscarriage rates.
Pregnancy rates per embryo transfer were higher in spring and summer than in winter, with the difference between winter and spring reaching statistical significance. Live birth rates in spring, summer, and autumn were also significantly higher than in winter.
The findings showed a consistent negative association between PM2.5 levels and ART outcomes, particularly the numbers of eggs, MII eggs, transferable embryos, and high-quality embryos.
Potential Mechanisms of PM2.5 Reproductive Toxicity
Once inhaled or ingested, PM2.5 particles may enter systemic circulation, reach the embryo, and impair optimal egg and embryo development. Studies report that PM2.5 exposure induces reactive oxygen species (ROS), mitochondrial dysfunction, DNA damage, and early apoptosis. These processes may reduce egg quality and impair embryo implantation.
In the female reproductive system, PM2.5 exposure may damage endometrial cells and cause oxidative stress and inflammation, making embryo attachment less favorable. It may also alter the expression of adhesion molecules, cell growth factors, and other substances essential to implantation.
By directly disrupting cellular processes, the toxic effects of PM2.5 on eggs and embryos ultimately impair reproductive outcomes.
PM2.5 also adversely affects male fertility. Research suggests that PM2.5 exposure may reduce sperm quality and density by targeting forkhead box protein O1 (FOXO1), lower testosterone, and increase testicular inflammation.
Study Conclusion
Overall, PM2.5 air pollution appears to have seasonal effects on ART outcomes, with winter live birth rates notably lower than in other seasons. PM2.5 reproductive toxicity is likely multifactorial, and further research is needed to clarify how it interferes with ART success.
News | Seasonal Air Pollution Adversely Affects IVF Success Rates
News | Seasonal Air Pollution Adversely Affects IVF Success Rates
A recent study published in BMC Public Health examined how seasonal fluctuations in fine particulate matter (PM2.5) pollution affect assisted reproductive technology (ART) outcomes. A sharp winter increase in PM2.5 pollution was closely associated with lower in vitro fertilization (IVF) success rates, adding to concerns about the potential impact of environmental pollution on fertility.
How Does Air Pollution Affect Fertility?
Assisted reproductive technology success is affected by age, lifestyle, genetics, and other factors. The effects of PM2.5 exposure on reproductive health, particularly ART outcomes, remain unclear.
Long-term exposure to PM2.5 air pollution significantly increases the risk of cardiovascular and respiratory disease. Existing evidence suggests that air pollution may also reduce fertility and increase pregnancy complications, particularly by lowering live birth rates. Clinicians therefore often recommend reducing air pollution exposure for at least three months before beginning IVF treatment.
Despite these observations, research on the effects of seasonal PM2.5 levels on ART outcomes remains limited.
Study Background
The study was conducted by Shangqiu First People’s Hospital and included 13,476 patients with infertility who received ART treatment between February 2018 and December 2022. About 4,000 patients were treated in spring and summer, compared with 2,300 in winter and 3,400 in autumn.
Researchers focused on PM2.5 exposure during the critical period from the start of controlled ovarian stimulation to 30 days after pregnancy testing, when optimal egg and embryo development and implantation are particularly important.
Study Findings
With the same ovarian stimulation medications used, several fertility measures across all seasons were associated with PM2.5 exposure. These included early-stage ART measures such as the number of eggs, the number of eggs reaching the second meiotic metaphase (MII), the number of transferable embryos, and the number of high-quality embryos.
After adjustment for age and expected seasonal variation, PM2.5 exposure was significantly negatively associated with pregnancy and live birth rates but had no significant effect on miscarriage rates.
Pregnancy rates per embryo transfer were higher in spring and summer than in winter, with the difference between winter and spring reaching statistical significance. Live birth rates in spring, summer, and autumn were also significantly higher than in winter.
The findings showed a consistent negative association between PM2.5 levels and ART outcomes, particularly the numbers of eggs, MII eggs, transferable embryos, and high-quality embryos.
Potential Mechanisms of PM2.5 Reproductive Toxicity
Once inhaled or ingested, PM2.5 particles may enter systemic circulation, reach the embryo, and impair optimal egg and embryo development. Studies report that PM2.5 exposure induces reactive oxygen species (ROS), mitochondrial dysfunction, DNA damage, and early apoptosis. These processes may reduce egg quality and impair embryo implantation.
In the female reproductive system, PM2.5 exposure may damage endometrial cells and cause oxidative stress and inflammation, making embryo attachment less favorable. It may also alter the expression of adhesion molecules, cell growth factors, and other substances essential to implantation.
By directly disrupting cellular processes, the toxic effects of PM2.5 on eggs and embryos ultimately impair reproductive outcomes.
PM2.5 also adversely affects male fertility. Research suggests that PM2.5 exposure may reduce sperm quality and density by targeting forkhead box protein O1 (FOXO1), lower testosterone, and increase testicular inflammation.
Study Conclusion
Overall, PM2.5 air pollution appears to have seasonal effects on ART outcomes, with winter live birth rates notably lower than in other seasons. PM2.5 reproductive toxicity is likely multifactorial, and further research is needed to clarify how it interferes with ART success.
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