The Evaluation of Menstrual Alterations in Mexican Women After Vaccination Against COVID-19.

Introduction Menstrual changes after COVID-19 vaccination suggest a secondary connection to the immune response to vaccination rather than a specific component of the vaccine. The evaluation of these alterations in women with the same and multiple vaccination schedules will provide valuable information. Methods An observational, cross-sectional study was carried out; data were collected through a survey of 164 vaccinated women at the American British Cowdray (ABC) Santa Fe Medical Center Hospital in Mexico City. The survey was validated by the Delphi method. Results The survey was applied from March 2023 to February 2024. Post-vaccination menstrual alterations occurred in 48.1%; the most frequent alteration was menorrhagia in 20.7% and pain accompanied by menstruation in 27.4%. Fifty-seven percent had a history of previous COVID-19 infection. There were no significant associations between changes in menstrual bleeding after vaccination, history of COVID-19 infection, and age group (p>0.9). However, women who received multiple doses of vaccines had a higher risk of suffering abnormalities in bleeding by 36.6%. Conclusion The incidence of menstrual disorders in this study post COVID-19 vaccination was 49%. Menstrual alterations in patients who received multiple doses and a single regimen were similar at 47% and 48%, where there is no statistical significance. The greatest number of menstrual alterations was seen in the first dose at 36%, probably due to the immunity they acquired after the different types of vaccination. Vaccination is a very effective way to prevent the severity of COVID-19 infection; it has an impact on menstrual bleeding in terms of menorrhagia and metrorrhagia. Vaccination against COVID-19 is associated with small changes in the menstrual cycle, without statistical significance. Women receiving the first dose of the vaccine had changes in the amount of bleeding specifically the amount.