When COVID-19 appeared on the scene late in 2019, the world had never seen it before. Fortunately, though, several companies had been working on messenger RNA (mRNA) as a way to create vaccines. In addition, researchers had already studied SARS, another virus in the same family as SARS-CoV-2. These factors contributed greatly to the rapid development of effective vaccines against COVID-19. As a result, though, we are still learning about some of the side effects these vaccines can cause. Some readers pointed out that postmenopausal bleeding is an unexpected reaction.
Vaccines and Postmenopausal Bleeding:
Q. Please address breakthrough bleeding for postmenopausal women. I experienced this last December 2021 after my first Moderna booster in October 2021. I had an ultrasound, a biopsy, and a D&C (only after a pregnancy test—at age 74!). My GYN could not tell me why I was bleeding again or what to expect.
I just read that 66 percent of the postmenopausal women in a COVID vaccine study experienced this. The CDC does not seem to appreciate that bleeding in her 70s would cause any female concern! We shouldn’t have to choose between COVID and alarming side-effects.
Postmenopausal Bleeding Can Be Alarming:
A. We can certainly understand why you were upset. Vaginal bleeding after menopause can be a sign of a serious problem such as fibroids, or in a few cases, uterine cancer. You were right to ask the doctor to check you.
When COVID started, nobody knew what effects the vaccine might have on menstruation. Scientists have since learned that vaccination can alter the cycle for a few months, without affecting fertility. (COVID infections may have a more severe and persistent effect.)
The study you cite was conducted as a web-based survey (Science Advances, July 15, 2022). There is one important caveat, however. People who respond to surveys in general and online surveys in particular don’t necessarily reflect the population at large. While 66 percent of the postmenopausal people in the survey reported bleeding after vaccination, that does not represent the proportion of all people receiving vaccines who shared your experience.
Total Number of Women Bleeding After Vaccination Is Not Huge:
In fact, another study looked at this question in a different way. Researchers at Kaiser Permanente reviewed the medical records of nearly 500,000 women at least 55 years of age (American Journal of Obstetrics and Gynecology, July 11, 2022). Prior to vaccination, 0.39 percent had postmenopausal bleeding. Afterwards, 0.47 percent experienced this. This is a definite increase.
The authors write:
“However, in absolute numbers, the observed increase represents fewer than 1 in 1000 additional women diagnosed with bleeding after vaccination compared to before vaccination.”
