Self-Reported Adverse Events of COVID-19 Vaccines on Menstrual Cycles

Abstract

Aim of Study: To investigate the adverse events of COVID-19 vaccinations on menstrual abnormalities in women in their reproductive period. Methods: Following a cross-sectional research design, this study included 102 women who had received the COVID-19 vaccinations. A study questionnaire adapted from the Menstruation after COVID vaccine (MECOVAC) survey was used for data collection. Results: Almost half of participants (48%) reported the incidence of menstrual abnormalities after receiving COVID-19 vaccinations, manifested as changes in frequency, length or quantity of menstruation. Participants received one, two or three doses of either Pfizer-BioNTech or Oxford-AstraZeneca vaccines. Adverse events of COVID-19 vaccines occurred mainly after the third doses of Pfizer and AstraZeneca (12.5% for both). The most frequent changes in quantity of menstrual blood among participants were variation in its quantity and having heavier menstruation (17.2% and 15.6%, respectively), which occurred after receiving the third dose of Pfizer vaccine, while menstrual blood became less among 25% of participants after receiving the third dose of AstraZeneca. Disturbance of personal life occurred in 44.9%, while 38.8% needed to visit a doctor, 26.5% underwent investigations and 32.7% took medications. Menstrual cycles of 51% returned to normal within 1-2 cycles, while those of 49% returned after more than two cycles. Conclusions: Women who receive COVID-19 vaccinations may have menstrual abnormalities. This change mainly occurs after the third dose, regardless of the brand of received vaccine. It is recommended that women be clearly informed after vaccination of the possibility of short-term menstrual abnormality and to seek proper medical advice in such conditions. Further studies are required to investigate the possible mechanisms behind these COVID-19 vaccines’ adverse events. Keywords: COVID-19 vaccination, adverse events, menstrual abnormality, Saudi Arabia