After reports of COVID-19 vaccines impacting women’s menstrual cycles, Reuters reports that the European Medicines Agency's (EMA) safety committee will look into a possible connection between the two.

After receiving either Pfizer or Moderna mRNA vaccines, some women have reported experiencing intense menstrual bleeding and lack of menstruation. The European agency clarified that changes in menstrual cycles were also associated with COVID-19 infection, and explained that menstruation complications can arise from fatigue and stress.

Earlier research from the National Institutes of Health found that COVID vaccines were associated with impermanent changes in the duration of menstrual cycles. The study showed that women who got vaccinated against the virus had moderately prolonged menstrual cycles following the shots when compared to people who did not receive the vaccine.

A study published last month in the American Journal of Epidemiology found that the COVID-19 vaccine does not hinder fertility in men or women. There was evidence, however, to imply that the virus itself can temporarily weaken fertility in men.

“These findings indicate that male SARS-CoV-2 infection may be associated with a short-term decline in fertility,” the authors wrote in the study. “COVID-19 vaccination does not impair fertility in either partner."