ABSTRACT
BACKGROUND: Vaccination can have an impact on menstruation, and this impact may be more notable in women with inflammatory gynecological pathologies such as endometriosis. OBJECTIVES: We aimed to investigate the impact of mRNA-based SARS-CoV-2 vaccines on menstrual cycle-related symptoms in women with endometriosis and assess the effect of hormonal therapy on potential SARS-CoV-2 vaccination-induced menstrual changes. DESIGN: A total of 848 women who received at least two doses of mRNA-based COVID-19 vaccines were prospectively recruited: 407 with endometriosis (endometriosis group) and 441 healthy controls (non-endometriosis group). METHODS: Data regarding demographics, clinical characteristics, hormonal treatment, and menstrual-associated symptoms in the first and second cycle after vaccination were collected through an online survey. RESULTS: A similar percentage of patients in both the endometriosis and the non-endometriosis group self-reported menstrual-associated changes the first (52.6% versus 48.8%, respectively) and second cycle after vaccination (29.0% versus 28.1%, respectively). Although the total symptoms recorded were not different between the two groups, several specific symptoms were statistically more frequent in the endometriosis group. These were pain disorders and fatigue in the first cycle after vaccination and pain disorders, menstrual headache and fatigue in the second cycle after vaccination. Bleeding frequency/regularity disorders were found to be more frequent in the non-endometriosis group in the first cycle after vaccination. Patients under hormonal treatment reported fewer changes in menstrual symptoms in the first and second cycle after vaccination compared with those not receiving this treatment. Similarly, patients in the endometriosis group receiving hormonal treatment reported fewer changes in menstrual-associated symptoms compared with those not following any hormonal treatment in the first and second menstrual cycle after the last vaccination. CONCLUSION: Women with endometriosis immunized with mRNA-based SARS-CoV-2 vaccines did not perceive greater worsening or new menstrual-associated symptoms after complete COVID-19 vaccination compared with healthy controls. Hormonal treatment may have a protective effect against worsened or new menstrual symptoms induced by COVID-19 vaccination.