Vaccination against Covid-19 helps prevent severe forms of the disease. However, the latter could have a side effect on menstruation and disrupt the menstrual cycle of vaccinees.
Fever, nausea, headache and pain in the arm are unpleasant but normal side effects after a vaccine. However, as a cycle becomes irregular, delayed periods are less so. Yet many vaccinated women have reported these side effects lately.
More painful and heavier periods
The alert comes from Twitter. Dr. Kate Clancy, medical anthropologist, shared on this social network her experience of unusually heavy periods after receiving the anti-Covid Moderna vaccine. In response to his tweet, dozens of similar testimonials and the idea of starting a study with people who have menstruated or formerly menstruated.
Helped by her colleague, Dr. Katharine Lee, postdoctoral fellow at Washington University School of Medicine, the researchers submitted a research proposal for Institutional Review Board approval to understand this dysfunction. They wrote that they expected 500 participants. “We hit this figure within the first two hours. The number of respondents has now exceeded 13,000”, revealed Dr. Clancy to the media Medium. “When I got my first injection of Moderna nine days later, I had a much heavier period than usual. I went from having no periods to having a rash. On the second day, I was still changing towels every hour and was very grateful to work at home “, she confides. For now, the data from the study is still being studied but there are many changes in the menstrual cycle according to the researchers.
Another study is also being carried out by the Womanizer brand of sextoys with their international panel of testers. The 552 people who had menstruated and vaccinated (first or second injection) responded to a survey. Thus, one in five people confided that anti-Covid vaccines cause a disruption in their menstrual cycle. In 31% of those polled, periods were heavier and 29% said it was more painful than usual. Finally, 22% noticed a period delay of a few days.
The return of periods for postmenopausal women
Questioned by the BBC News, Dr. Victoria Male, reproductive immunologist at Imperial College London, said some postmenopausal women and people taking hormones to stop their periods have reported bleeding. Transgender men also contacted Drs Clancy and Lee to warn them that they had been bleeding after the vaccine. But this disruption of the menstrual cycle is not inexplicable, Dr Male explains that “The lining of the womb is part of the immune system – in fact, there are immune cells in almost every part of the body […] After vaccination, many chemical signals that can affect immune cells circulate in the body. This could cause loss of the uterine lining and lead to bleeding or menstruation earlier ”.
A temporary disruption without danger to health
For researchers Lee and Clancy, there is no reason to worry even if menstrual changes are linked to the vaccines. “A vaccine activates your immune system. It will create some inflammation.”, explains Dr. Clancy in the columns of Medium. “What’s so cool about the uterus is that it’s a site where tons and tons of tissue remodeling is happening all the time. It is constantly making new tissue and constantly differentiating tissue,” she adds.
For the American gynecologist Jen Gunther, she puts it into perspective on her website, dedicated to news and women’s health, these disturbances which prove to be temporary and harmless, “Consider potential menstrual irregularities as a side effect of the vaccine, just like fever, it is a sign of activation of the immune system. And just as a fever doesn’t make people permanently hot after a vaccine, menstrual irregularities won’t be permanent either.
