Researchers Conduct Survey to Understand Menstruation Changes from COVID-19 Vaccine

Questions are emerging as to whether women’s menstrual cycles are impacted by COVID-19 vaccines, and two women researchers are conducting a survey to figure out if there are impacts and if so, why they are happening.

“A lot of people still think of periods as … something we shouldn’t talk about. People who tend to be in charge have historically been able-bodied white men, and it’s not part of their experience so they don’t think to ask these things,” said Katharine Lee, postdoctoral research scholar, Division of Public Health Sciences Department of Surgery at Washington University School of Medicine in St. Louis.  

When the survey was started, Lee and her colleague Kathryn Clancy, associate professor at University of Illinois, expected to get a few hundred or thousand people to respond, not expecting a giant sample size.

However, as of Monday, there are already over 92,000 people who have taken or started the survey.  

The idea to start the survey originated a month ago when Lee and a friend received the vaccine on the same day and noticed changes in their menstrual cycles. 

Lee’s friend has an intrauterine device used for birth control, and normally doesn’t have a period but noticed she did have one that was heavy and accompanied by cramps. Lee experienced a light period when normally she wouldn’t have any, and bad low back cramps. 

To understand what might be happening, she started a Twitter thread asking others if they had a similar experience and was met with a slew of responses that sparked the idea of putting a survey together. 

Lee said changes in menstruation, which may or may not  be caused by the vaccine, vary by individual, and that so far from anecdotal stories, she has noticed the vaccine appears to be impacting menstruation for people who are on gender affirming hormones, post-menopausal women, and people on IUDs or other forms of menstrual oppression medications who normally wouldn’t menstruate.

“I suspect that being informed this happened could go a long way in being prepared,” said Lee. 

However, for people who do have a normal menstrual cycle, researchers plan to examine the timing between receiving the vaccine and change, if any, in menstruation.  

Typically, a period occurs every 21 to 35 days and lasts two to seven days..  

One of the hypotheses for why periods may be impacted by COVID-19 vaccines is that the vaccine activates the autoimmune response in the body, and that response activates all other inflammatory pathways as well.  

Researchers also asked respondents what vaccine they received to try to understand how menstruation changes might vary based on the type of vaccine received. The Moderna and Pfizer require two shots nearly a month apart, and the Johnson and Johnson only requires one.  

“We are hearing from a lot of people that they are experiencing something after each. If you have your period after the second you get another cycle as well,” she said.  

There are currently no known long-term impacts known from an infrequent change in menstruation, as a period being disturbed for a couple of cycles does not impact fertility outcomes. 

There is no cutoff date for individuals to participate in the survey, and Lee and her team are currently in the process of hiring research assistants to review the data and produce a descriptive report which prioritizes some of the results by this summer.  

“We hope that remembering to ask about things like peoples experience with periods is something we should do in clinical trials. It wasn’t one of the questions they asked people, and it is a thing that a lot of people pay attention to for their health and understanding of their body,” said Lee.