Impact of Pfizer-BioNTech COVID-19 Vaccination on the Menstrual Cycle

Objective: To evaluate the effect of Pfizer-BioNTech Coronavirus disease-2019 (COVID-19) vaccination on the menstrual cycle. Method:This cross-sectional survey study investigated whether Pfizer-BioNTech COVID-19 vaccination affected the menstrual cycle of women who had regular cycles.Results: One hundred and sixty two of 327 (49.5%) patients who had regular cycles expressed that their menstrual cycle had been affected after vaccination.Univariate analysis revealed a statistically significant relationship between age, body mass index (BMI), parity, smoking, pads per day, intrauterin device (IUD) and the incidence of menstrual change after vaccination.The factors identified by multivariate analysis as being independently related with the menstrual disorders following vaccination were BMI [odds ratio (OR) 1.09, 95% confidence interval (CI) 1.01-1.17,p=0.023], smoking (OR 2.19, 95% CI 1.28-3.78,p=0.005), pads per day (OR 1.42, 95% CI 1.14-1.75,p=0.005) and IUD (OR 5.1, 95% CI 1.99-13.0,p=0.001). Conclusion:Approximately half of the participants declared menstrual disorder after vaccination.BMI, smoking, number of pads per day, and IUD were found to be independent risk factors for menstrual changes.