COVID-19 Vaccination May Negatively Affect Menstruation

COVID-19 vaccination may negatively affect menstruation, according to study results published in Influenza and Other Respiratory Viruses.

This cross-sectional study was conducted in Jordan, Palestine, Syria, Egypt, Sudan, and Libya from November 2021 to December 2021. Researchers compared changes in menstruation among women who had received at least 1 COVID-19 vaccine dose vs women who were unvaccinated. Participants’ menstruation patterns and demographic characteristics were self-reported via online questionnaire. Chi-square testing was used to establish the relationship between menstruation and COVID-19 vaccination status, and logistic regression was used to examine the association between vaccination status and menstruation outcomes, with adjustments for demographic factors.

Among a total of 4942 participants included in the final analysis, the mean (SD) age was 24.02 (5.73) years, the mean BMI was 23.56 (4.79) kg/m², and 59.1% were vaccinated against COVID-19 infection. In addition, 1838 (48.7%) participants reported prior COVID-19 infection, and 74.2% reported a regular cycle.

Participants who were vs were not vaccinated reported higher rates of pelvic pain (84.5% vs 81.6%; P =.006), back pain (82.9% vs 77.9%; P <.001), thigh pain (63.9% vs 61.0%; P =.045), nausea (43% vs 40%; P =.036), and fatigue (89.7% vs 87.1%; P =.005). Vaccinated participants also were more likely to report use of analgesics without a prescription (62.7% vs 57.2%; P <.001).

The researchers evaluated pain during menstruation among vaccinated participants using a 10-point scale. Participants who received the mRNA-1273 or BNT162b2 vaccine reported higher mean pain scores (6.43 and 5.94, respectively), as well a longer duration of bleeding (5.76 and 5.92 days, respectively), when compared with those who received other COVID-19 vaccines.

Further analysis was performed after adjustments for demographic characteristics determined to be related and unrelated to menstruation. Results indicated COVID-19 vaccination was a significant predictor for increased occurrence of pelvic pain, back pain, nausea, general weakness, menstrual pain, unprescribed analgesics use, bowel movement, and loose stools.

Limitations of this study include the cross-sectional design and the use of both self-reported data and convenience sampling.

Despite these findings, “COVID-19 vaccination can reduce the risk of infection and severe disease and numerous studies have confirmed that the benefits of vaccination outweigh the risks,” the researchers noted.