Researchers from MIT, University of Colorado Denver, and the Clue app have published the largest study to date examining air pollution’s impact on menstrual health, analyzing data from 2.2 million menstrual cycles across 230 cities in the United States, Mexico, and Brazil.
The study, published in The Lancet Planetary Health, found that higher concentrations of fine particulate matter (PM2.5) in the air correspond with increased frequency of menstrual cycle irregularities, particularly longer cycles. This connection suggests disrupted endocrine and reproductive functioning associated with pollution exposure.
Unlike previous research that relied on retrospective self-reporting, this study utilized longitudinal cycle tracking data from Clue users combined with satellite measurements of air pollution levels. While short-term pollution exposure did not show immediate effects, the research indicated that PM2.5 exposure in prior cycles appeared to affect cycle regularity later.
“Menstrual cycle length and variability are a vital indicator of women’s health. Research has shown that highly variable menstrual cycles can be associated with an increased risk of premature mortality, cardiovascular disease, type 2 diabetes, cancer, and infertility,” said Priyanka deSouza, PhD, MSc, MBA, MTech. “The impacts of pollution on menstrual cycle length have been understudied, as few epidemiologic cohorts track menstrual cycle information.”
The findings build on prior research linking air pollution to reproductive outcomes like preterm birth and infertility, but focus specifically on menstrual health – an area that researchers say has been neglected due to the persistent gender health gap in scientific research.
“Clue is helping close the gender health gap by making large-scale research into women’s health faster and more feasible than ever before,” said Amanda Shea, Fractional Chief Science Officer at Clue. “By analyzing millions of de-identified cycles tracked in the app alongside environmental data, we’ve taken a new approach to exploring how external factors like pollution might influence reproductive health.”
The research methodology included analyzing data collected between 2016 and 2020 from 92,550 Clue users. Satellite-derived estimates of PM2.5 concentrations were aggregated at the city level and matched to corresponding cycle data.
“This study gives us a unique look at how air pollution might affect menstrual cycle length in three different countries,” noted Dr. Shruthi Mahalingaiah of Harvard T.H. Chan School of Public Health and Massachusetts General Hospital. “PM2.5 is already known to harm human health, especially the heart and lungs. This study shows that it may also affect ovulation and menstrual health.”
For those concerned about air quality’s potential impact on their health, the researchers recommend monitoring air quality and limiting exposure during high pollution days, tracking menstrual cycles to establish personal patterns, and consulting healthcare professionals about any concerning cycle changes.
