Common side effects of the COVID-19 vaccine include headaches, a sore arm and exhaustion—but for some women, the effects go beyond the norm. Thousands of people are reporting disruptions to their menstrual cycle.

The National Institutes of Health (NIH) announced on August 30 they would be awarding $1.67 million to study potential links between the COVID-19 vaccine and irregular menstrual cycles. The research will build on smaller, existing studies and period-tracking app data. One such existing study comes from Illinois State professor Kate Clancy and alumna Katharine Lee, Ph.D. in anthropology. The two women launched a social media survey and received more than 140,000 reports from women claiming cycle disruptions.

Lee told NPR in August that most of the reports they received detail short-lived effects. "We started hearing a lot about breakthrough bleeding, from people on long-acting reversible