You Are Not the Only One Who Has Experienced Menstrual Changes After the COVID-19 Vaccine
When COVID-19 vaccines first became available, some people noticed unexpected menstrual bleeding after they received the vaccine. Some trans men were among those affected, which must be pretty darn weird if you think you’ve run out of your period and then all of a sudden you’re having your period.
Menstrual changes or unexpected bleeding were not tracked in the original COVID vaccine studies, so no one could tell if these changes were part of a vaccine-related regimen. So a research team circulated a survey asking people about their menstrual-related experiences with the vaccine, and the results have now been published . In short: if this happened to you, you are definitely not alone.
How many people have had heavy or unexpected bleeding after vaccination?
Before I tell you the results, it’s important to know one thing: The survey is not based on a representative sample, so we don’t know how common these menstrual side effects are in the general population. We just know how common they were among the people who took the survey. On the one hand, people who had problems were more likely to complete the questionnaire; but the researchers note that there may be reasons why people who have had changes in their bleeding or new bleeding may be less likely to complete the questionnaire. After all, we don’t know.
With that, here are the results:
Of the respondents with normal menstrual cycles, 44% said their cycle continued as normal, and 42% said they bled more heavily. Among people who do not usually menstruate, but who have had them before, the majority of respondents reported breakthrough bleeding. This included 71% of people taking long-acting reversible contraceptives such as the IUD, 66% of people who had gone through menopause, and 39% of people taking sex-confirming hormones.
Why did it happen?
We don’t know why this happened, but the study’s authors say it was premature last year to tell women there was no “biological mechanism” by which a vaccine could cause breakthrough bleeding.
But the authors note that menstrual cycle changes have been reported in the past with other vaccines, including vaccines against typhoid, hepatitis B, and HPV. And because the uterus has to switch between the functions of bleeding, clotting and repair, which turn on the immune system, something like a vaccine that activates the immune system and causes inflammation can affect these processes. Senior author Katherine Clancy told Technology Networks : “When the immune system is activated by something like a vaccine, it will have all sorts of downstream effects, including on the uterus.”
This does not mean that bleeding is necessarily bad for your health. The authors note that “the uterine reproductive system is flexible and adapts to stressors to withstand short-term challenges in a way that preserves long-term fertility.” We already know that stress (both physical and psychological) can affect the menstrual cycle.
However, if you’re experiencing bleeding that you don’t expect, it may be a good idea to get tested. Unexpected bleeding when you don’t normally have your period can sometimes be an early sign of cancer . But it’s good to know that it can also be a side effect of the COVID vaccine.
Ultimately, we still don’t know why the more severe and breakthrough bleeding occurred, and we don’t know how common it actually was. But at least there is information to say that yes, it is a thing , and researchers are studying it further.