Several women say they have experienced heavier and more painful periods since getting the COVID-19 vaccine, with several also revealing that they have had breakthrough bleeding in the middle of a cycle after getting the shot.
Dr. Kate Clancy, an associate professor at the University of Illinois, tweeted in February that she’d been hearing talk of people who had experienced changes in their menstruation since getting one or two vaccine shots.
Her Twitter thread has prompted more women to share their menstrual concerns on Twitter, revealing their heavy flow, worsened cramps, and irregular timing — with one saying she spent 16 days bleeding after getting the Johnson & Johnson shot.
Dr. Clancy first tweeted on February 24, but her thread has continued to find other Twitter users who are seeking out explanations for their symptoms.
‘A colleague told me she has heard from others that their periods were heavy post-vax,’ she wrote.
‘I’m curious whether other menstruators have noticed changes too? I’m a week and a half out from dose 1 of Moderna, got my period maybe a day or so early, and am gushing like I’m in my 20s again.
‘I’m on day 3 of my period and am still swapping out extra long overnight pads a few times a day. Typical for me at this time is maybe one or two regular pads (though extra absorbent, Always Infinity ones) for the whole day,’ she went on.
‘Does this have to do with the way the vax response is mounting a broader inflammatory response, possibly moreso because of the lipid nanoparticle or mRNA mechanism? Either way I am fascinated! Inflammation + tissue remodeling = extra bleedypants!’ she added.
Soon, other Twitter users were chiming in with their own experiences. Though several have said that their periods have not changed, many who have taken the time to comment reported differences.