Covid-19 Vaccines and the Menstrual Cycle: Bleeding Patterns and Potential Menstrual Effects of COVID-19 Vaccinations

October, 2022

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After being contacted on social media about reports of menstrual disturbances after SARS-CoV-2 vaccination, Learn Body Literacy and its fertility awareness education initiative #FAMTaughtMe conducted a web survey from September 2021 to April 2022. The survey collected a broad range of menstrual experiences of people with active menstrual cycles after SARS-CoV-2 vaccination. In addition to measuring cycle length differences, the survey explores additional markers through biometric tracking such as cervical fluid changes, clotting patterns, spotting events, ovulation, and how vaccine timing within the menstrual cycle phases changes its potential effects. In this survey, 19.2% of people with ovulatory menstrual cycles had a heavier menstruation than usual after dose 1, while 70.5% reported no change after dose 1. 23.1% report heavier bleeding than usual after dose 2, with 56.4% of participants reporting no change after dose 2. Other participants noted various menstrual anomalies such as delayed ovulation, delayed menses, shorter cycles (potential anovulatory cycles), spontaneous bleeding, heavy bleeding, lighter bleeding, and cramping or pain changes. We must continue to push researchers to design studies which acknowledge the infradian rhythm of the menstrual cycle and include more useful information about how people who menstruate react to different therapeutics, vaccines, surgeries, and procedures. Learn Body Literacy encourages more studies to be conducted so that the hormonal, immune, inflammatory, and hemostatic changes to menstrual cycles after vaccination can be better understood.