Effect of COVID-19 vaccine on menstrual experience among females in six Arab countries: A cross sectional study

Background: There have been varying reports on the potential occurrence and severity of changes to menstruation including the median cycle length, days of bleeding, bleeding heaviness, and menstrual pain, following receipt of COVID-19 vaccinations. We aimed to assess potential postvaccination menstrual changes in women residing in the Middle East. Methods: We implemented a cross-sectional online survey-based study. Data about the participants' demographic characteristics, menstruation experience, and vaccination status were collected and analyzed among six Arab countries. Results: Among 4942 menstruating females included in this study, females who had received one or more doses of COVID-19 vaccination reported a higher frequency of back pain, nausea, tiredness, pelvic pain with periods, unprescribed analgesics use, and passage of loose stools. They also reported higher scores describing average and worst menstrual pain. Fully vaccinated females reported heavier flow and more days of bleeding. Conclusion: Our findings indicate that COVID-19 vaccine may have an effect on menstruation in terms of menstrual pain and bleeding heaviness. The evidence needs to be further investigated in longitudinal studies.