According to a study published this Friday (15.07.2022), more than 40 percent of people with a cycle of menstruation regulars reported having heavier periods after receiving a flu shot COVID-19[feminine]. About 39,000 people took part in the online survey, 42% of whom said they bleed more heavily after a vaccinewhile 44% reported no change.
Women with conditions such as endometriosis and polycystic ovary syndrome were more likely to have increased bleeding. However, there were also survey participants who did not menstruate normally but reported bleeding: this includes 71% of people using long-acting reversible contraception, 39% of people on hormone treatment to affirm their sex and 66% of menopausal people. .
Victoria Male, a researcher in reproductive immunology at Imperial College London in Britain, says that while the study is not representative of the population as a whole, the results help to understand what types of people are those most likely to bleed more than normal.
Reproductive health issues?
A coronavirus vaccine can delay menstruation. However, the study concluded that it did not affect reproductive health as menstruation was only delayed by one day, while bleeding duration was virtually unchanged. Moreover, these changes turned out to be mostly temporary.
However, Katherine Lee, the study’s lead author and a biological anthropologist at Washington University School of Medicine, says it’s important to take side effects seriously.
If anyone is concerned about the changes they are going through, they should see a doctor, he says, in an interview with DW.
Why do vaccines increase bleeding?
A person’s menstrual cycle is controlled by hormones produced by the hypothalamus, pituitary and ovaries. This prepares the female body for implantation of the fertilized egg. Hormonal changes, due for example to psychological stress, intense exercise such as running a marathon or fasting, easily disrupt menstrual cycles.
According to Lee, the immune response caused by the flu vaccine covid probably causes heavy menstrual bleeding. Specifically, after the vaccine, small proteins called cytokines cause inflammation, alerting the immune system that it’s time to do its job.
The author of the study assures that one of the reasons for carrying out the survey was to create greater awareness of women’s health. “People just don’t talk about menstruation much in public,” says Lee. For us, transparency is very important and that people understand that short-term effects (like increased bleeding) can be part of a safe vaccine, he adds.