ABSTRACT
PURPOSE: As the use of the messenger RNA (mRNA) BNT162b2 (Pfizer-BioNTech) Coronavirus disease 2019 vaccine has grown, reports on menstrual changes have arisen. We aimed to examine menstrual bleeding patterns and endometriosis-associated symptoms after receiving the mRNA BNT162b2 SARS-CoV-2 vaccine in women with endometriosis, as compared to the control group. METHODS: This is a questionnaire-based cross-sectional study including a total of 174 women. The study group included 86 women with a confirmed diagnosis of endometriosis and the control group included 88 women with no diagnosis or suspected diagnosis of endometriosis. Each woman completed a questionnaire on menstrual bleeding patterns and endometriosis-associated symptoms before and after receiving two doses of the BNT162b2 vaccine. Primary outcomes were changes in amount or length of menstrual bleeding, rates of intermenstrual bleeding and worsening in dysmenorrhea in the endometriosis patient group, as compared to the control group. Secondary outcomes included changes in all endometriosis-associated symptoms. RESULTS: In our cohort, women with endometriosis were more likely to experience changes in bleeding patterns (women with endometriosis: 39.5%, control group: 31.0%, p = 0.02), and a significant worsening in endometriosis-associated symptoms with an almost 4.3-fold worsening in dysmenorrhea [95% CI 1.9-9.9, p < 0.01] and 5.5-fold odds for any worsening in symptoms in endometriosis patients, as compared to the control group [95% CI 2.7-11.1, p < 0.01]. CONCLUSION: In our cohort, endometriosis was shown to be a significant risk factor for worsening of menstrual symptoms, after receiving the SARS-CoV-2 BNT162b2 mRNA vaccine. Further research is needed to confirm these findings.