Background: Women across the world reported menstrual cycle changes after receiving COVID-19 vaccines. This may increase vaccine hesitancy. The aim of this study is to assess the impact of COVID-19 vaccines on menstrual cycle among women living in Riyadh. Methods: The study utilized online self-administered questionnaire targeting females at the childbearing period, eligible to receive COVID-19 vaccine and not pregnant. Results: In our study, a total of 762 females with a mean age of (32.19±8.71) years. Participants were, mostly, unemployed (59.6%) non-smoker (93.6%) married (61.1%) Saudis (88.5%), (63.2%) carried a bachelor or diploma degree, (81%) were stressed. About quarter had thyroid disorders, received medications and were previously infected. (96.9%) were vaccinated and (87.3%) got 2 doses. The bulk received Pfizer-BioNTech vaccine (1st dose=80.7%, 2nd doses=75.4%). (82%) noticed changes and (80.6%) experienced symptoms 1-3 months after vaccination, (17.4%) delayed menses. Abdominal pain (24.4%) was predominant. Females with previous infection had less menstrual changes after vaccination (P-value= 0.001, AOR=0.475, CI 95%= 0.323-0.700). Having symptoms was significantly different between education levels. “Diploma or bachelor’s degree” vs “High school or less” (P-value =0.004, AOR=2.054, CI 95%= 1.257-3.356), “Postgraduate studies vs High school or less” (P-value=0.002, AOR=2.492, CI 95%= 1.396-4.448). COVID-19 vaccination was not associated with neither menstrual changes nor symptoms related to it. Conclusion: Previous infections had a protective effect against changes in menstruation after receiving the COVID-19 vaccines. Those at school age and postgraduate suffered more. Vaccination itself didn’t cause neither changes nor symptoms related to menstrual.
Keywords: COVID-19, vaccination, menstrual cycle.