Covid-19 Vaccines Temporarily Change Menstrual Cycles, Study Shows

Almost half of the participants recent research who menstruated regularly at the time of the survey reported more heavy bleeding during their period after receiving the Covid-19 vaccine. Others who did not normally menstruate, including transgender men, people taking long-acting birth control, and postmenopausal women, have also experienced unusual bleeding.

The new study – the largest to date – expands research this has highlighted the temporary effects of Covid-19 vaccines on menstrual cycles, but has so far focused mainly on cisgender women who are menstruating.

Although vaccines are largely prevention of death and serious illness Due to the low number of reports of side effects, many medical experts initially shrugged off the concerns when women and people of different genders began reporting erratic menstrual cycles after vaccinations.

To better understand this post-vaccination experience, researchers at the University of Illinois at Urbana-Champaign and the Washington University School of Medicine in St. Louis. In April 2021, Louis distributed an online survey to thousands of people around the world. After three months, the researchers collected and analyzed more than 39,000 responses from people aged 18 to 80 about their menstrual cycles. All survey respondents were fully vaccinated with Pfizer-BioNTech, Moderna, Johnson & Johnson, or other vaccines approved outside the United States. And to the best of their knowledge, the participants did not contract Covid-19 prior to the vaccination.

A study published Friday in the journal Science Advances shows that 42% of women with regular menstrual cycles experienced more bleeding after vaccination, while 44% had no change and 14% had lighter periods. In addition, 39 percent of respondents receiving sex-confirming hormone treatment, 71 percent of people taking long-acting contraceptives, and 66 percent of postmenopausal women experienced breakthrough bleeding after one or both injections.

“I think it’s important that people know that this can happen so that they don’t get scared, shocked, or run out of supplies,” said Katherine Lee, a biological anthropologist at the Washington University School of Medicine in St. Louis. …Louis… Louis and the first author of the study.

Dr. Lee cautioned, however, that the study did not compare the results with a control group of people who had not been vaccinated. And it is possible that people who observed changes in their cycles after vaccination were more likely to participate in the survey. However, the results are consistent with smaller studies reporting menstrual cycle changes after vaccination with more robust controls.

Importantly, the new study also found that certain demographics may be more likely to experience menstrual changes, and the study could help them prepare better, says Dr. Lee said. For example, heavier menses were more likely to occur in older people. Survey respondents who used hormonal contraception have been pregnant in the past or have been diagnosed with reproductive disorders such as endometriosis, fibroids or polycystic ovary syndrome were also more likely to bleed more heavily during menstruation. People who self-identified as Hispanic or Latino also tended to report more heavy bleeding. And people who have experienced others side effects of vaccinessuch as fever or fatigue were also more likely to experience irregular periods.

Postmenopausal women who were slightly younger, averaging around 60 years of age, were more likely to experience breakthrough bleeding after vaccination than older women. But the type of vaccine the postmenopausal women received, whether they had other side effects such as fever, or whether they had a previous pregnancy, did not appear to affect their bleeding.

Some level of menstrual variability — the number of days of bleeding, the amount of bleeding, and the length of the cycle — is normal.

“Our menstrual cycles are not perfect clocks,” the doctor said. Alison Edelman, professor of obstetrics and gynecology at the Oregon Health and Science University, who has also studied the effects of Covid-19 vaccines on menstruation.

Hormones secreted by the hypothalamus, pituitary gland, and ovaries regulate the menstrual cycle and can be influenced by both internal and external factors. Stress and illness, weight loss or gain, calorie restriction, and intense exercise can change the typical pattern of menstruation.

The endometrium, which lines the uterus and is shed during menstruation, is also associated with the immune system. Because of the role it plays in remodeling uterine tissue and providing protection against pathogens, it is possible that when vaccines activate the immune system, which they are supposed to do, they also somehow cause downstream effects in the endometrium, causing disruption. in your menstrual cycle, doctor. Edelman said. And some people may be more sensitive to immune or hormonal changes in their body.

In his study, Dr. Edelman found that some women menstruated a day or two later than usual after vaccination against coronavirus. But the changes were temporary – menstruation, as a rule, returned to normal after one or two cycles.

If you find any new or unusual bleeding patterns, look into it. The menstrual cycle can be thought of as another vital sign, like body temperature or blood pressure, that gives an indication of your health. Jennifer Cavasse, a reproductive endocrinologist at Emory University, who was not involved in the study.

“A significant change in menstrual interval or bleeding profile warrants further investigation to ensure there is no underlying endocrinological, hematological, or anatomical cause,” says Dr. Qawvass said. For example, breakthrough bleeding in people who normally no longer have periods can also be warning sign of cervical, ovarian, uterine, or vaginal cancer.

That being said, minor changes in your menstrual cycle if you have regular periods should not be a cause for concern and do not require you to change anything you normally do. Qawvass said.

Clinical trials and other studies have already established that Covid-19 vaccines Safely as well as effective and are unlikely to affect fertility in the long term.

Experts agree that the havoc that Covid-19 can cause throughout your body, including potential lingering effectsfar worse than any side effects caused by vaccination against the disease.

People who have previously had a fever after a shot can schedule their next dose for a day when they don’t have to go to work, the doctor says. Edelman said. But you shouldn’t let temporary menstrual changes prevent you from getting a full vaccination or boost. As the number of cases rises again, delaying vaccination by two weeks or longer could significantly increase the risk of contracting Covid-19, she said.

However, it’s important to monitor your body’s response to the vaccination, and health officials should acknowledge concerns about menstrual fluctuations in addition to warning people about the risk of contracting Covid-19, said Keisha Ray. Bioethicist at McGovern School of Medicine at UTHealth Houston.

Increased transparency about menstrual changes or other side effects of vaccination may also have another benefit: reducing people’s hesitancy about vaccines.

“We are trying to be truthful. We are trying to confirm the life experience of people,” said the doctor. Lee. In turn, she hopes the new study will help improve conversations about people’s health and lead to more inclusive clinical trials in the future.