Abstract

Background and Aims:
Post-COVID19 vaccination menstrual irregularities have emerged as an evolving concern among women of reproductive age. This study evaluates the association between COVID-19 vaccination and menstrual cycle changes among reproductive-aged women in Riyadh, Saudi Arabia.
Methods:
A cross-sectional study conducted among 700 participants via social media using a validated, self-administered Arabic questionnaire, adapted from existing literature. The tool was refined through rigorous back-translation and expert review (ACP = 96.6%). The questionnaire covered four domains: demographics, medical history, vaccination details, and menstrual changes. Kuder-Richardson coefficient of 0.7 confirmed the instrument’s reliability and internal consistency. Statistical analysis was performed using SPSS. The study received IRB approval, and all participants provided voluntary informed consent. Data confidentiality was maintained through anonymization and the exclusion of personal identifiers.
Results:
Significant changes occurred in premenstrual syndrome (doses 1 and 2: P=0.010, 0.020) and cycle duration (P=0.024). Moderna significantly affected pain severity (P=0.007), unlike Pfizer or AstraZeneca. Flow and cramps were unaffected. Age, BMI, and employment were significant predictors of duration changes, while education and smoking were not.
Conclusions:
COVID-19 vaccination is associated with significant changes in PMS symptoms and cycle duration, with the Moderna vaccine specifically impacting pain severity. Age and BMI serve as key predictors of these changes.

Key words: COVID-19 vaccines, menstrual cycle changes, reproductive age, Saudi Arabia