Association Between SARS-CoV-2 Immunization and Menstrual Complaints?

Studies based mainly on self-reports and tracking apps have suggested that COVID-19 vaccination might be associated with menstrual disturbances. In this study, investigators used Swedish national databases to examine associations between SARS-CoV-2 vaccination and healthcare visits for menstrual complaints by 3 million women between December 2020 and February 2022. Visits within the first 7 days after vaccination were presumed to be unrelated to vaccination, as a woman would be unlikely to notice symptoms and obtain an appointment within 1 week. Contacts from 8 through 90 days after immunization were considered to be possibly vaccine related.

Among premenopausal women (age range, 12–49), vaccinated women had a slightly higher incidence of visits for menstrual disturbances than did not-yet-vaccinated women in both the 0-to-7–day and the 8-to-90–day windows. Among postmenopausal women (age range, 45–74), the incidence of visits for postmenopausal bleeding was similarly higher in both windows for recently vaccinated women than for not-yet-vaccinated women. However, for all these comparisons, hazard ratios were about 1.1 and of marginal statistical significance. Results were similar after each dose and for each vaccine (i.e., Pfizer, Moderna, and AstraZeneca).