Covid vaccines caused temporary menstrual changes in more than 40% of people with regular cycles, study finds

Covid vaccines caused temporary menstrual changes in more than 40% of people with regular cycles, study finds

An analysis published Friday in the journal Science Advances found that 42% of people with regular menstrual cycles said they bled more heavily than usual after vaccination. Meanwhile, 44% reported no change and around 14% reported a lighter period. Among nonmenstruating people — those post-menopause or who use certain long-term contraceptives, for example — the study suggests many experienced breakthrough or unexpected bleeding after their Covid shots.

The new survey started in April 2021, around the time people began to report unexpected bleeding and heavier flow post-vaccine. However, these anecdotes were at the time met with the rebuttal that there was no data linking menstrual changes to vaccination.

That was both true and indicative of a larger problem. Individuals who took part in Covid vaccine trials were not asked if they experienced menstrual changes.

Previously:

Coronavirus Vaccines and Menstruation