Abstract
Background: A global concern about a possible association between COVID-19 vaccines and menstrual disturbance has been raised. Moreover, women who have experienced menstrual changes are worried about the length of the side effects and are hesitant to receive booster doses. Therefore, the aim of this study is to evaluate the impact of the COVID-19 vaccine on all features of the menstrual cycle, including cycle length, amount of bleeding, and pain.
Methodology: We retrospectively analyzed menstrual cycles following at least two doses of COVID-19 vaccines; the cycle changes within the individual pre-vaccination and post-vaccination were compared. All reproductive-aged females from 18 to 45 years who fit the inclusion criteria were included in the study and categorized into five sub-categories based on age to investigate whether certain age groups were most affected. The data were collected through a well-structured self-administered questionnaire. Participants obtained their vaccination information (date, type of vaccine) from Tawakkalna, the official COVID-19 application in the Kingdom of Saudi Arabia. IBM Corp. Released 2019. IBM SPSS Statistics for Windows, Version 26.0. Armonk, NY: IBM Corp was performed in data entry and statistical analysis. Variables were described as frequency and percentage, as all were categorical. To investigate the association between menstrual changes and its possible associated factors, we used the Chi-square test, and the statistical significance was determined at p<0.05.
Results: The online questionnaire received responses from a total of 1092 reproductive females. However, out of which, 419 were not fitting into the inclusion criteria. Thus, a total of 673 females were included in the final report. Overall, the changes in the menstrual cycles after both COVID-19 vaccine doses were observed among 46.7%, mainly more menstrual pain in 22.9% following the first dose compared with 21.4% after the second. Menstrual changes were observed among almost two-thirds of women in the age groups 18-22 years (65.2%) and 38-45 years (65.4%) compared with only 43.5% of those in the age group 23-27 years, p<0.001. The Moderna vaccine was associated with the highest rate of menstrual changes (65.4%), whereas Oxford-AstraZeneca was associated with the lowest rate (44.9%), p=0.040. The duration of changes in the cycles after the COVID-19 vaccine (one dose or both) was less than one month among 42.5% of females, whereas it was three months or more among 27.1%.
Conclusion: The COVID-19 vaccination is associated with a minor and transient change in the menstrual cycle, resulting mainly more menstrual pain and increased bleeding.