Menstrual bleeding changes following COVID-19 vaccination reported in new study
USA: Changes to menstrual bleeding are not uncommon or dangerous after COVID-19 vaccination among people who menstruate, yet attention to these experiences is required to build trust in medicine, researchers suggest in a study published in Science Advances.
In early 2021, many people began sharing their experiences of unexpected menstrual bleeding after SARS-CoV-2 inoculation. Katharine M. N. Lee, Washington University in St. Louis School of Medicine, St. Louis, MO, USA, and colleagues, therefore, investigated this emerging phenomenon of changed menstrual bleeding patterns among a convenience sample of currently and formerly menstruating people using a web-based survey.
The researchers established an emergent, exploratory, mixed-methods survey instrument intended to capture a wide range of responses from current and formerly menstruating adults. In the study, they shared results from their first round of analyses (N = 39,129), as well as the ways that this early exploration has made it possible to establish the parameters of the phenomenon of postvaccine menstrual change.
They focused on findings related to menstrual bleeding (in people who menstruate regularly) or breakthrough bleeding (in people who do not currently menstruate) from the first 3 months of data collection
They sought to address the following research questions: (i) What is the range of menstrual bleeding changes reported by regularly menstruating respondents after being administered the SARS-CoV-2 vaccine? (ii) Are there trends among those with a changed bleeding pattern to help determine proximate mechanisms acting on the uterus? (iii) To what extent are nonmenstruating respondents reporting breakthrough bleeding after being administered the SARS-CoV-2 vaccine?
Based on the survey, the researchers revealed the following:
- In this sample, 42% of people with regular menstrual cycles bled more heavily than usual, while 44% reported no change after being vaccinated.
- Among respondents who typically do not menstruate, 71% of people on long-acting reversible contraceptives, 39% of people on gender-affirming hormones, and 66% of postmenopausal people reported breakthrough bleeding.
- Increased/breakthrough bleeding was found to be significantly associated with age, systemic vaccine side effects (fever and/or fatigue), history of pregnancy or birth, and ethnicity.
The researchers conclude, "changes to menstrual bleeding are not uncommon or dangerous, yet attention to these experiences is necessary to build trust in medicine."
Reference:
The study titled, "Investigating trends in those who experience menstrual bleeding changes after SARS-CoV-2 vaccination," was published in the journal Science Advances.
DOI: 10.1126/sciadv.abm7201
