Association between menstrual cycle disturbances and COVID-19 vaccination among women in Saudi Arabia: a national cross-sectional study

Background: The COVID-19 pandemic raised concerns about the effects of vaccination on menstrual cycles. This study investigated the association between COVID-19 vaccination and menstrual irregularities among women aged 18–41 in Saudi Arabia. Methods: A national cross-sectional survey conducted in August 2022 included 397 participants meeting specific criteria. Data on vaccination history, menstrual patterns, and psychological well-being were collected via a structured online questionnaire. Results: Of the participants, 61.5% reported menstrual changes after at least two COVID-19 vaccine doses, and 32.7% experienced changes after the third dose. Common changes included altered cycle intervals (63.5%), duration (52%), and blood volume (48.8%). Psychological status improved post-lockdown and was significantly associated with menstrual changes (p = 0.013). Most participants received the Pfizer vaccine, but no significant link was found between vaccine type and irregularities. Despite these changes, only 10.7% sought medical care, while 42.1% reported a return to normalcy without intervention. Conclusions: A majority of participants associated menstrual changes with COVID-19 vaccination, consistent with prior studies. These findings highlight the need for further research on vaccine-related effects to support women's health.