Menstrual-Related Disturbances Following SARS-CoV-2 Vaccination: A Spanish Retrospective Observational Study in Formerly Menstruating Women (preprint)

To date, the impact of COVID-19 vaccination on formerly menstruating women remains unknown. For this reason, a retrospective observational cross-sectional study was conducted (N= 548) using an online survey. General characteristics, medical history, and adverse events following COVID-19 vaccination were recorded. In comparison with the first dose, significantly higher percentages of respondents experienced menstrual-related disturbances (dose 1: 38.5% vs. dose 2: 44.8%; McNemar=9.15; mid P-value=0.002), as well as the simultaneous occurrence of two or more of these symptoms (dose 1: 11.2% vs. dose 2: 15.3%; McNemar=13.53; mid P-value=0.044) after receiving the second one. Among them, those related with the length and flow stand out, being of long-term nature in about 17-20% of cases. Interindividual factors influencing this unexpected event after receiving the dose 1 may include weight (AOR 1.02, CI 95% 1.01–1.03, P<.001), perimenopause (AOR 2.28, CI 95% 1.37–3.77, P=.001), pre-existing diagnoses of non-autoimmune rheumatic/articular conditions (AOR 0.31, CI 95% 0.10–1.00, P=0.05), hormonal contraceptive use (AOR 0.25, CI 95% 0.07-0.82, P=0.02), suffering from other vaccine side effects − such as arm pain (AOR 0.61, CI 95% 0.39–0.95, P=0.03), headache (AOR 0.53, CI 95% 0.35 – 0.80, P=.003), swollen glands (AOR 0.29, CI 95% 0.15 – 0.60, P=.001) and nauseas (AOR 0.35, CI 95% 0.14 – 0.86, P=0.02) – and the number of previous pregnancies (AOR 2.70, CI 95% 1.54 – 4.76, P=.001). Formerly menstruating women may experience long-term menstrual-related disturbances following COVID-19 vaccination.

COVID-19 Disease and Menstrual-Related Disturbances: A Spanish Retrospective Observational Study in Formerly Menstruating Women (preprint)

After three years of the onset of the pandemic, there is scarce evidence about how COVID-19 disease affect the female reproductive system, and consequently, the menstrual cycle. Since the common causes of secondary amenorrhea are considered as exclusion criteria in the studies about menstrual changes following SARS-CoV-2 infection, the prevalence of this event and the influencing factors in formerly menstruating women remains unknown. A retrospective observational cross-sectional study was conducted on Spanish adult women (N= 17,512), using an online survey; a subpopulation of SARS-CoV-2-infected-formerly menstruating women was included in the present analysis (n= 72). Collected data included general characteristics, medical history, and specific information about COVID-19 disease. 38.9% of the respondents experienced menstrual-related disturbances after suffering from the COVID-19 disease, unexpected vaginal bleeding being the most common (20.8%). Other alterations related with the length – “shorter” by 12.5% − and the flow − “heavier than usual” 30.3% − of the menstrual bleeding were reported. The binary logistic regression showed that being a perimenopausal woman (AOR 4.608, CI 95%, 1.018 – 20.856, p = 0.047) and having heavy menstrual bleeding (AOR 4.857, CI 95%, 1.239 – 19.031, p=0.023) are influential factors. This evidence could help health professionals to provide scientifically up-to-date information to their patients, empowering them to actively manage their reproductive health, especially in those societies where menstrual health is still a taboo.