Although the jury is still out on man-made climate change, the reality is that environmental pollution is very real and its negative effects result in unwanted outcomes.
Pollution is not only behind respiratory and cardiovascular ailments, but also plays a role in the results of in vitro fertilization. Scientists have now discovered that pollution negatively impacts assisted reproduction.
According to a study by the Hospital del Mar Institute for Medical Research (IMIM) in Barcelona, women who undergo these treatments and are exposed to high levels of contamination have a 25% higher risk of not getting pregnant. The probability of a miscarriage also increases by 40%.
The impact of pollution on fertility has long been known. Exposure to contaminating particles reduces semen quality and increases the risk of spontaneous abortions, says Dr. Miguel Ángel Checa, head of the Barcelona Infertility Research Group at IMIM.
“There were already retrospective studies, but we wanted to see what happens in a vulnerable group, such as people with fertility problems that undergo in vitro fertilization,” says the researcher, who presented the study at the International Symposium on Lifestyle and Fertility, held this Friday at the Biomedical Research Park of Barcelona.
Scientists recruited about 200 patients to conduct the study. “When they came to do IVF, we asked them if they wanted to participate and we did previous studies to rule out factors that could influence the evolution of the treatment,” said Czech.
Researchers took into account, through meters dispersed throughout urban areas, the levels of air pollutants 15 days before implantation, 3 days before, the same day and 7 days later.
The measurement focused on NO2 and suspended particles from road traffic. The previous analysis of the baseline population already pointed out that the average exposure of women exceeded the recommendations of the World Health Organization.
Scientists analyzed 486 embryonic transfers. Of these, 215 ended in pregnancy, although only half evolved to term. “We found that exposure to high rates of suspended particles (PM2.5) increases the risk of not getting pregnant by 25% and the risk of spontaneous abortion by 40%,” says Czech.
The high probability of abortion, says the doctor, responds to the fact that it is a relative risk, that is, when compared with a population of vulnerable patients, such as women undergoing in vitro fertilization, although they are not exposed to high pollution rates. In this group, the risk of abortion is 10%, although it can reach 40%, depending on the age at which treatment begins.
According to the study, it is the high rates of suspended particles during the three days prior to embryo transfer and the day of its realization that directly impact on the increased risk of abortion or failure to achieve pregnancy.
Researchers are committed to influencing traffic regulation and organization policies to combat the effects of pollution on health.
“We are not just dying from respiratory diseases. Our reproductive system is also affected,” warns the researcher.
The signatories of the study, whose results are part of a doctoral thesis plan to publish the finding also in a scientific journal.