COVID-19 Vaccines and the Menstrual Cycle: A Cross-Sectional Study

Objective: This study aimed to explore the impact of various COVID-19 vaccines on the menstrual cycle of Jordanian women. Materials and Methods: We conducted a retrospective analysis of tracked menstrual changes using an anonymous questionnaire written in the local language. We received 732 responses, and after exclusions, 617 responses were analyzed. The questionnaire covered six sectors: demographics, medical history, COVID-19 infection and vaccination status, obstetric and gynecological history, menstrual cycle history, and specific questions about cycle length, flow, and any symptoms before and after each vaccine shot. Participants included Jordanian females who had received any type of COVID-19 vaccine. Results: Among the participants analyzed, two-thirds were between the ages of 20-35, and the majority had a normal BMI (59.6%). Most participants were single, nulliparous, and had never used contraception methods (79.3%, 82.0%, and 93.8%, respectively). Only a small percentage had other risk factors influencing menstrual cycle changes, such as surgical procedures (10.5%) and specific medications (8.10%). Baseline menstrual information was recorded. Forty percent of participants experienced changes in menstrual duration, and approximately one-fifth reported heavier and more severe premenstrual syndrome (PMS) symptoms. Body mass index (BMI) was directly correlated with bleeding intensity after vaccination. Parity was weakly directly proportional to bleeding intensity after vaccination. However, BMI and parity did not significantly correlate with menstrual duration, menstrual cycle length, PMS symptoms, or cramps after vaccination. Conclusion: In a population of young, non-sexually active women with a normal BMI, most participants did not experience significant changes in their menstrual cycles after receiving the COVID-19 vaccine. Only one-fifth of participants reported shorter duration, heavier bleeding, more frequent, more painful, and more severe PMS symptoms post-vaccination.