Women and other menstruators have been reporting changes to their periods after getting the COVID-19 vaccine; late periods, increased bleeding, breakthrough bleeding, and worse pain are among the symptoms reported. New research confirms and measures some of these changes. On average, vaccinated people got their periods about one day late, and people who got two vaccines within a single menstrual cycle had periods about 4 days late. Although disrupted menstrual cycles typically returned to normal quickly, this knowledge can help people plan for the possibility of temporary menstrual cycle changes with COVID-19 vaccination.
“A study of nearly 20,000 people around the world shows that getting vaccinated against covid can change the timing of the menstrual cycle. Vaccinated people experienced, on average, about a one-day delay in getting their periods, compared with those who hadn’t been vaccinated. …
Any change in getting your period can be stressful, triggering worries about an unplanned pregnancy or an illness, and people have expressed frustration that public health officials didn’t warn them about the possible side effect or do more research before rolling out the vaccines.”
Note: The research discussed in this article does not include women on birth control or trans, nonbinary, and agender people.