image: Carrie Nobles, assistant professor in the UMass Amherst School of Public Health and Health Sciences, is an environmental and reproductive epidemiologist. view more
Credit: UMass Amherst
Funded by a new grant from the National Institutes of Health (NIH), a University of Massachusetts Amherst environmental and reproductive epidemiologist aims to develop a more robust understanding of the effects of ambient air pollution on women’s reproductive health.
Carrie Nobles, assistant professor in the School of Public Health and Health Sciences, will use the two-year, $650,000 exploratory/developmental research grant from the NIH’s National Institute of Environmental Health Sciences to identify mechanisms and susceptible reproductive processes across the menstrual cycle and early pregnancy.
Ultimately, findings will provide the foundation for identifying ways to improve reproductive health and informing public policy on pollution standards.
Ambient air pollution, such as traffic and power-plant emissions, is associated with increases in inflammation and oxidative stress that may inhibit the establishment of a healthy pregnancy by disrupting endocrine function, ovulation, implantation and placentation, Nobles explains.
Previous, smaller studies by Nobles and colleagues have linked air pollution to fertility at the broad population level, “but we don’t understand exactly how and who is most affected,” says Nobles, who is also analyzing the impact of air pollution and other environmental factors on men’s fertility in another NIH-funded study.
Nobles will incorporate data from the completed preconception time-to-pregnancy study known as EAGeR (Effects of Aspirin in Gestation and Reproduction), which evaluated the effect of low-dose aspirin on live-birth rates. The study includes detailed information on 1,228 participants during six menstrual cycles when they are attempting to get pregnant.
“Around the time of ovulation and also around the time of implantation of the embryo, exposure during those points to higher levels of air pollution does seem to relate to a lower probability of getting pregnant and also a higher risk of pregnancy loss,” says Nobles about findings from studies involving couples seeking infertility treatment. “But there are very few studies that have this fine detailed information on the timing of things like ovulation, the earliest possible detection of pregnancy and, potentially, a pregnancy loss. So, we will be able to look at these acute exposures that are hard to detect.”
Nobles will estimate participants’ exposure to ambient air pollution during biologically informed windows of the menstrual cycle and early pregnancy by looking at the EPA’s Community Multiscale Air Quality (CMAQ) models where they live.
For a smaller group of 288 women, Nobles will look at urinary levels of polycyclic aromatic hydrocarbons (PAHs), chemicals found in vehicle exhaust, cigarette and wood smoke, and grilled or charred food. She also will examine two biomarkers for oxidative stress mechanisms. “This will let us understand more about how these effects are happening,” Nobles says.
For the group of women who received low-dose aspirin, Nobles will assess whether the anti-inflammatory and anti-platelet actions of aspirin reduce the impact of air pollution exposure.
Nobles hypothesizes that air pollution exposure around ovulation and implantation will change reproductive hormones and reduce fertility. Pollution exposure during critical windows in early pregnancy is also expected to increase risk of pregnancy loss.
She expects that the impacts of air pollution among the women who received low-dose aspirin will be weaker.