When women started reporting longer periods and heavier-than-normal bleeding after getting Covid vaccines last year, there was little data to back it up.
Although they made up around half the participants in Covid vaccine trials, women were not asked about any menstrual changes as part of that process. Since then, several studies have revealed that Covid vaccines can indeed induce short-term changes in menstrual cycles.
So a growing chorus of researchers is calling for further study of vaccines’ effects on menstruation. Collecting this type of data during the Covid vaccine trials, they say, could have prevented distress among those who experienced abnormal changes to their cycles and assuaged fears about the shots at a time when misinformation abounded.