Do covid vaccines affect menstruation?

Almost half of the participants in a recent study menstruating regularly at the time of the survey reported heavier bleeding during their periods after receiving the COVID-19 vaccine. Other people who usually don’t have periods, such as transgender men, people taking long-acting contraceptives, and postmenopausal women, have also had unusual bleeding.

The new study, the largest to date, expand investigations which show the temporary effects of COVID-19 vaccines on menstrual cycles, but have so far focused primarily on menstruating cisgender women.

Although vaccines have largely averted deaths and serious illnesses With few reported side effects, concerns were first dismissed by many medical experts when women and people of various genders began reporting erratic menstrual cycles after receiving the injections.

To conocer greater estas experiencias posteriores a la vacunación, investigadores de la Universidad de Illinois en Urbana-Champaign y de la Escuela de Medicina de la Universidad de Washington en St. Louis distribuyeron en abril de 2021 una encuesta en línea a miles de personas de todo the world. After three months, the researchers collected and analyzed more than 39,000 responses from people between the ages of 18 and 80 about their menstrual cycles. All of the people who responded to the survey had been fully vaccinated, with vaccines from Pfizer-BioNTech, Moderna, Johnson & Johnson, or another approved outside the United States. And, to their knowledge, the participants had not contracted COVID-19 before being vaccinated.

The research, published Friday in the journal Science Advances, shows that 42% of people with regular menstrual cycles experienced heavier bleeding after vaccination, while 44% reported no change and 14% reported heavier periods. light. In addition, 39% of respondents on gender-affirming hormonal treatments, 71% of those on long-acting contraception, and 66% of postmenopausal women experienced intermittent bleeding after one or both vaccinations.

“I think it’s important for people to know this can happen, so they don’t panic and get shocked and run out of supplies,” said Katharine Lee, a biological anthropologist. at Washington University School. of medicine in Saint-Louis and first author of the study.

Lee cautioned, however, that the study did not compare the results with a control group of unvaccinated people. And it’s possible that people who saw changes in their cycles after vaccination were more likely to take the survey. However, the results are consistent with smaller studies that have reported menstrual changes after vaccination with stronger controls.

Importantly, the new study also found that certain demographic groups may be more likely to experience menstrual changes, and the study may help them better prepare, Lee said. For example, older people are more likely to have heavy menstrual flow. Respondents who have used hormonal contraceptives, who have been pregnant in the past, or who have been diagnosed with a reproductive disease such as endometriosisthem fibroids or the polycystic ovary syndrome they were also more likely to have heavier bleeding during their periods. People who identified as Hispanic or Latino also tended to have heavier bleeding. And people who have lived other vaccine side effectssuch as fever or fatigue, were also more likely to experience irregular periods.

Slightly younger postmenopausal women, with a median age of 60, were more likely to have intermittent bleeding after vaccination than older women. But the type of vaccine received by postmenopausal women, whether or not they had other side effects, such as fever, or had ever been pregnant, did not seem to have an effect on their bleeding.

It is normal for there to be some variation in menstruation: the number of days of bleeding, the intensity of the flow and the length of the cycle.

“Our menstrual cycles aren’t perfect clocks,” says Alison Edelman, professor of obstetrics and gynecology at Oregon Health & Science University, who has also studied the impact of COVID-19 vaccines on menstruation.

Hormones secreted by the hypothalamus, pituitary and ovaries regulate the monthly cycle and can be affected by internal and external factors. Stress and illness, weight loss or gain, calorie restriction, and strenuous exercise can alter typical menstrual patterns.

The endometrium, which lines the uterus and sheds during menstruation, has also been related to the immune system. Because of its role in remodeling uterine tissue and protecting against pathogens, it’s possible that when vaccines activate the immune system, which they’re supposed to do, they also somehow trigger another side effects in the endometrium, which causes disruption of the menstrual cycle, Edelman said. And some people may be more sensitive to immunological or hormonal changes in their body.

In her research, Edelman discovered that some women’s periods were one or two days later than usual after being vaccinated against the coronavirus. But the changes were temporary: periods usually returned to normal after one or two cycles.

If you experience any new or unusual bleeding, write it down. The menstrual cycle can be seen as another vital sign, like body temperature or blood pressure, that provides clues about your health, said Jennifer Kawwass, a reproductive endocrinologist at Emory University, who was not involved. in the study.

“A significant change in menstrual cycle interval or bleeding pattern warrants further investigation to ensure that there is no underlying endocrinological, hematological, or anatomical cause,” Kawwass said. Intermittent bleeding in people who no longer have their periods normally, for example, can also be a sign of warning against cancer of the cervix, ovaries, uterus or vagina.

That said, a subtle shift in your menstrual cycle, if you have regular periods, shouldn’t be a cause for concern and doesn’t require you to change anything you normally do, Kawwass said.

Clinical trials and other studies have already established that COVID-19 vaccines are sure there efficient and what unlikely to affect fertility long-term.

Experts agree that the havoc COVID-19 can wreak throughout the body, including the potential lingering effectsis far worse than any side effect caused by vaccination against the disease.

People who have already had a fever after a vaccine can schedule their next dose on a day when they don’t have to go to work, Edelman said. But you shouldn’t let temporary menstrual changes keep you from completing your immunization schedule or getting your boosters. As cases rise again, delaying vaccination for two weeks or more can significantly increase the risk of contracting COVID-19, he said.

Still, it is important to monitor the body’s response to vaccination, and public health officials need to acknowledge concerns about variations in the menstrual cycle, as well as warn people about the dangers of contagion from COVID-19, said Keisha Ray, a bioethicist at UTHealth Houston’s McGovern. Medicine School.

“We try to be honest. We try to validate people’s lived experiences,” Lee said. In turn, he hopes the new research will help improve people’s health conversations and lead to more inclusive clinical trials in the future.

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