Impact of COVID Vaccines on Menstrual Cycles
Kedar nath last edited by
Soon after COVID-19 vaccinations became available, anecdotal reports of changes in menstrual cycles appeared and were amplified by social media. In a report published in the January 2022 issue of ACOG's "Green Journal," which received extensive media attention, investigators used data from a widely used fertility-awareness app known as Natural Cycles. This study assessed whether COVID vaccination is associated with changes in menstrual cycle characteristics in US women age 18-45 years who reported regular cycles and were not using hormonal contraceptives.
Arif Bhatt last edited by
@kedar-nath The app prompted users to report receipt or nonreceipt of COVID vaccination, including vaccine type. Based on International Federation of Gynecology and Obstetrics criteria, changes of less than 8 days in cycle length were considered normal. Among almost 4000 women with evaluable menstrual cycle data, more than half were vaccinated during the study period. Overall, receipt of vaccination was associated with a less than 1-day increase in cycle length, and the proportion of women experiencing changes in cycle length of 8 days or more was 4%-5%. This was similar among vaccinated and unvaccinated women.