COVID-19 Vaccination and Menstrual Cycle Changes: A Review Study

ABSTRACT

Background: There has been increasing public concern that COVID-19 vaccines cause menstrual cycle disturbances. There are concerns that vaccination against Coronavirus disease 2019 (COVID-19) may be associated with abnormal menstrual cycles. Unfortunately, clinical trials of the current COVID-19 vaccines did not collect menstrual cycle outcomes post-vaccine. According to social media reports, menstrual disturbances are much more common, but these disturbances are temporary. Menstrual cyclicity is an overt sign of health and fertility. This normal variability may be perceived as concerning, especially in conjunction with a new exposure such as COVID-19 vaccination. This study evaluates the menstrual changes after COVID-19 vaccination in three studies. Method(s) We analyzed three retrospective cohort studies of menstrual cycle data that were collected prospectively from October 2020 to March 2021 in the UK and US and Oslo. Result(s) The first study in the UK found that among premenopausal vaccinated individuals who menstruated in the 12 months preceding the survey, 20% reported any changes to their menstrual cycles up to 4 months after receiving their first injection. In the second study that was done in the US (2019), individuals had been evaluated to determine whether COVID- 19 vaccination was associated with menstrual cycle disturbances during cycles when vaccination occurs. They found that individuals with normal menstrual cycles experienced small variations in cycle length. The third study that was done in Oslo (2021) showed the prevalence of unusually heavy and prolonged bleeding, short intermenstrual intervals, and increased pain during periods was higher after the first vaccine dose compared to the prior vaccination. Conclusion(s) There is currently limited data to evaluate the impact of vaccination on menstrual health, and it limits our ability to sufficiently address these concerns.