The Vaccine May Cause Breakthrough Bleeding in People Taking Hormones to Suppress Menstruation

An online survey by researchers at Washington University in St. Louis, presented in April 2022, was the first to specifically assess breakthrough bleeding caused by the COVID-19 vaccine in people who take testosterone or other hormones that suppress menstruation.

RELATED: Stopping Menstrual Periods Is Safe, Experts Say

The survey included individuals with a range of gender identities, such as transgender, nonbinary, or gender-fluid.

The researchers discovered that, of 552 respondents who said they used testosterone or other gender-affirming hormones and did not usually menstruate, one-third reported breakthrough bleeding after they received a COVID-19 vaccine, 9 percent reported chest or breast soreness, and 46 percent reported having other symptoms they would usually associate with a period, such as cramping and bloating. The study did not report the percentage of respondents who experienced breakthrough bleeding before vaccination, and it’s important to note that menstruation is not always reliably suppressed with these therapies. The team is currently conducting a follow-up survey to see if these symptoms are temporary or long-lasting.

A coauthor of the study, Katharine Lee, PhD, a postdoctoral research scholar in the division of public health sciences at Washington University in St. Louis, suspects the culprit for these changes is the immune and inflammatory response triggered by the vaccine. “There is a huge mobilization of your immune system. And I think it could just be a little bit of cellular cross-talk that is disrupting this process.”

How Your Period Responds to Stress

And what if you noticed menstrual changes after you caught the virus or even if you didn’t catch it? That is also quite possible. Sometimes stress alone can throw your period out of whack, and if you’re someone who’s usually very regular, even slight differences are noticeable. And in case you need any convincing, there’s no question that the coronavirus pandemic and other distressing developments in recent history qualify as a major form of stress.

Apart from the illness caused by the disease itself, the pandemic has brought the kinds of intense personal challenges that can really disrupt lives, whether that’s losing a loved one, managing remote work for yourself, or getting divorced.

So it’s not exactly surprising that some people who menstruate have been experiencing disruptions — from skipped periods to longer cycles to changes in bleeding patterns. This can happen if someone becomes infected with the novel coronavirus or if they’re simply dealing with the prolonged stress of the pandemic, according to a report published in June 2020 in MedPage Today.

“What we can say about COVID-19 and its effects on the menstrual cycle is comparable to what we can say about other viral infections and prolonged periods of stress — menstrual disruptions are likely to occur,” says Taraneh Shirazian, MD, the director of global women’s health and an assistant professor of obstetrics and gynecology at NYU Langone Health in New York City. “If you get COVID-19, it’s a stress on the body and a major stress on the hypothalamic pituitary adrenal (HPA) axis,” which is the body’s central stress response system.

During times of stress, the HPA axis stimulates the release of the stress hormone cortisol to help the body prepare to fight or flee from a threat. With ongoing stress, “increased cortisol levels can affect a woman’s menstrual cycles,” Dr. Shirazian says. In addition, with prolonged periods of stress, the stress response system can burn out, and the HPA axis can be suppressed, which drives down the pituitary production of follicle stimulating and luteinizing hormones (FSH and LH), which then drive down ovarian production of estrogen and progesterone.

With complete suppression of the HPA axis, a woman may experience amenorrhea, the absence of periods. With partial suppression, a woman could have spotty periods or periods of bleeding every few weeks. “There isn’t one clear pattern we can expect — women respond differently to suppression of the HPA axis,” Shirazian says.