Abstract
Background: After widespread vaccination against COVID-19, a number of unknown complications were reported, including changes in the menstrual cycle. Objectives: Considering the limited information available on this subject, this study was carried out with the aim of studying the prevalence of menstrual disorders in women following COVID-19 vaccination. Methods: This cross-sectional study was performed in 2022 on 400 women of reproductive age who had received at least 2 doses of the COVID-19 vaccines. The participants were chosen from health centers in the city of Asadabad of Hamedan Province in Iran using the convenience sampling method. The research tool was a researcher-made questionnaire that investigated demographics and changes in the menstrual cycle. Data analysis was carried out using descriptive statistics (frequency and percentage) and inferential statistics (chi-square and Fisher's exact tests). Results: The findings showed that 36.3, 42.5, and 48.01% of the participants experienced menstrual disorders after the first, second, and third doses of vaccination, respectively. Significant relationships were observed between the number of vaccination doses and menstrual disorders (P ≤ 0.001). Furthermore, there were correlations between menstrual disorders and the type of administered vaccine in the first (P = 0.003) and third (P ≤ 0.001) doses. Conclusions: In this study, a number of menstrual complications were observed in women after the administration of the COVID-19 vaccine, and such complications were intensified by an increase in the number of vaccines administered. Since this study was cross-sectional, it cannot be said with certainty whether the administration of the COVID-19 vaccine results in menstrual disorders or not. For this purpose, there is a need for more case-control or prospective studies.