Nearly half of the participants of a recent study who were menstruating regularly at the time of the survey reported heavy bleeding during their periods after receiving the COVID-19 vaccine. Others who did not menstruate normally – including transgender men, people on long-acting contraceptives and post-menopausal women – also experienced abnormal bleeding.
The new study – the largest to date – expands on research that has uncovered the temporary effects of COVID-19 vaccines on the menstrual cycle, but has so far focused primarily on menstruating women.
Although vaccines have largely prevented deaths and serious illness with few reported side effects, many medical experts initially dismissed concerns when women and gender-diverse people reported irregular menstrual cycles after receiving the shots. started reporting.
To get a better understanding of these post-vaccination experiences, researchers from the University of Illinois at Urbana-Champaign and Washington University School of Medicine in St. Louis distributed an online survey to thousands of people around the world in April 2021. After three months, the researchers collected and analyzed more than 39,000 responses from individuals aged 18 to 80 about their menstrual cycles. All survey respondents were fully vaccinated — with Pfizer-BioNtech, Moderna, Johnson & Johnson vaccines or any other that was approved outside the United States. And as far as they are aware, the participants did not contract COVID-19 before getting vaccinated.
Research published Friday in the journal Science Advances shows that 42 percent of people with regular menstrual cycles experienced heavy bleeding after vaccination, while 44 percent reported no change and 14 percent reported lighter periods. Additionally, 39 percent of respondents on gender-affirming hormone treatment, 71 percent of those on long-acting contraceptives, and 66 percent of postmenopausal women successfully experienced bleeding after one or both of their shots.
“I think it’s important that people know this can happen, so they don’t get scared, they don’t get shocked and they don’t get caught without supplies,” said a biochemist at Washington University School of Medicine in St. Anthropologist Katherine Lee said. Louis, and first author of the study.
However, Dr. Lee cautioned that the study did not compare results with a control group of people who had not been vaccinated. And it’s possible that people who noticed changes in their cycles after vaccination may be more likely to take part in the survey. Nevertheless, the findings match those of smaller studies that have reported post-vaccination menstrual changes 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 prepare them better, Dr. Lee said. For example, those who were older were more likely to have heavy menstrual flow. Survey respondents who used hormonal contraception, were pregnant in the past or were diagnosed with a reproductive condition such as endometriosis, fibroids or polycystic ovarian syndrome were also more likely to have heavy bleeding during their periods. People who identified as Hispanic or Latino also reported heavy bleeding. And those who experienced other side effects of the vaccine, such as fever or fatigue, were also more likely to experience irregular periods.
Postmenopausal women who were slightly younger, around the average age of 60, were more likely to experience breakthrough bleeding after the vaccine than those who did not. But the type of vaccine given to postmenopausal women, whether they had other side effects such as fever or whether they had had a previous pregnancy, had no effect on their bleeding.
Why do these changes happen?
Some level of variation in menstruation — the number of days you bleed, the heaviness of your flow, and the length of your cycle — is normal.
“Our menstrual cycles are not perfect clocks,” said Dr. Alison Edelman, professor of obstetrics and gynecology at Oregon Health and Science University, who has also studied the effect of COVID-19 vaccines on menstruation.
Hormones secreted by the hypothalamus, pituitary gland, and ovaries control the menstrual cycle, and they can be influenced by both intrinsic and extrinsic factors. Stress and illness, weight loss or weight gain, calorie restriction and intense exercise can all alter typical menstrual patterns.
The endometrium, which lines the uterus and is shed during menstruation, has also been linked to the immune system. Because of its role in remodeling uterine tissue and providing protection against pathogens, it is possible that when vaccines activate the immune system, which they should, they somehow trigger downstream effects in the endometrium, Which causes a mistake. In your menstrual cycle, Dr. Edelman said. And some individuals may be more sensitive to immune or hormone changes in their bodies.
In his research, Dr. Edelman found that some women’s periods come a day or two later than usual after they’ve been vaccinated against the coronavirus. But the changes were temporary – menstruation returned to normal after one or two cycles.
What to do if you notice menstrual irregularities after the Kovid vaccine?
If you experience any new or unusual patterns of bleeding, take note. The menstrual cycle can be considered another important sign, just like your body temperature or blood pressure, which provides clues about your health, said Dr. Jennifer Kavas, a reproductive endocrinologist at Emory University who was not involved in the study. Were.
“A significant change in the menstrual interval or bleeding profile warrants further investigation to ensure that there is no underlying endocrinologic, hematologic or anatomic cause,” said Dr. Kavas. For example, in people who no longer have normal periods, breakthrough bleeding can also be a warning sign of cervical, ovarian, uterine or vaginal cancer.
That being said, subtle changes in your menstrual cycle, if you have regular periods, shouldn’t be a cause for concern and don’t require you to change anything that you normally do, Dr. Kavas said.
Clinical trials and other studies have already established that COVID-19 vaccines are safe and effective and are unlikely to affect fertility in the long run.
Should you get vaccinated at a certain time in your cycle?
Experts agree that COVID-19 can cause chaos, including possible effects throughout your body, far worse than any side effects caused by vaccination against the disease.
People who have had a fever after a shot before can plan their next dose on a day when they won’t have to go to work, Dr. Edelman said. But that shouldn’t stop you from vaccinating or promoting temporary menstrual changes altogether. As cases continue to rise again, delaying vaccination by two weeks or more can significantly increase your risk of getting COVID-19, she said.
Still, it’s important to track your body’s response to vaccinations, and public health officials should acknowledge concerns about menstrual cycle variation in addition to warning people about their risk of getting COVID-19, Keisha said. Ray said a Bioethics specialist at McGovern Medical School at UTHealth Houston.
Increased transparency about menstrual changes or other side effects of vaccination may also have another benefit: reducing people’s hesitation to get vaccinated.
“We’re trying to be truthful. We’re trying to validate people’s life experiences,” Dr. Lee said. In turn, he hopes the new research can improve conversations about people’s health. and lead to more inclusive clinical trials in the future.