The National Institutes of Health has announced a $1.67 million study to investigate allegations that the COVID-19 vaccine may have unintended consequences for reproductive health.

The virus causes the COVID-19 disease, is commonly known as the novel coronavirus, or SARS-CoV-2 virus or The CCP (Chinese Communist Party) virus.

In the U.S., the three CCP Virus vaccinations—Pfizer, Moderna, and Johnson & Johnson—have been publicly available to all adults for just over six months. But, as The Lily reported in April, even in the early days of vaccination deployment, some women were experiencing irregular periods after receiving their doses.

Shana Clauson, 45, told the Washington Post’s women’s news site about her experience after taking the vaccine at the time, then again this week, noting that her period came earlier and heavier than usual. She was one of several who took to social media to express their experiences.

“Is this not being discussed, or is it even being looked at or researched because it’s a ‘woman’s issue?’ ” Clauson speculated to the Lily last spring.

The National Institutes of Health (NIH) appears to have noticed Clauson and others’ concerns. They declared on Aug. 30 that they were planning to conduct such research, with up to half a million participants, including teens and transgender and nonbinary people, New York Post reported.

The study, commissioned by the National Institute of Child Health and Human Development (NICHD) and the Office of Research on Women’s Health, has enlisted researchers from Boston University, Harvard Medical School, Johns Hopkins University, Michigan State University, and Oregon Health and Science University.

The study will monitor initially unvaccinated volunteers for about a year to see how they alter after each dosage. In addition, some organizations will expressly exclude members who are using birth control or gender-affirming medications, both of which might affect periods.

“Our goal is to provide menstruating people with information, mainly as to what to expect, because I think that was the biggest issue. Nobody expected it to affect the menstrual system because the information wasn’t being collected in the early vaccine studies,” said NICHD Director Diana Bianchi in a statement to The Lily.

According to the National Institutes of Health, alterations in the menstrual cycle could result from various lifestyle conditions during a pandemic, including the stress of lifestyle changes or even dealing with illness. Furthermore, because the immune and reproductive systems are inextricably intertwined, the idea that an immune-boosting vaccination can interrupt the normal menstrual cycle is plausible, as evidenced by prior vaccine uptake studies.

It’s also worth mentioning that the vaccine does not cause infertility, and the Centers for Disease Control and Prevention advises pregnant women to get it.

According to Bianchi, the funds were given to researchers already working on menstruation and reproductive health studies using NIH-funded programs.

One of them is Laura Allen Payne, a Harvard Medical School assistant professor of psychiatry heading a two-year study on adolescent girls’ menstrual pain. According to a 2016 CDC report, that age group is critical to research since they’re “at risk for potential hormonal, biological and neurological changes that could put them at risk for [chronic] pain,” which affects women on average more than males.

Payne will look at the menstrual cycles of roughly 80 girls before and after they are vaccinated as part of a broader study to see if and how the vaccines affect their cycles—and, perhaps, their discomfort.

According to Bianchi, three other research initiatives at BU, Johns Hopkins, and OHSU will collaborate with period-tracking apps Clue, Natural Cycles, and Kindara, which will offer researchers de-identified data from users who have given their agreement to participate.

Stacey Missmer, obstetrics, gynecology, and reproductive biology professor at Michigan State University, will use the money to expand two studies she’s already running—on infertility and endometriosis—to see if the vaccines, as well as pandemic-related stress and anxiety, are affecting periods.

Because menstrual cycle abnormalities are not “really not a life and death issue,” according to Bianchi, the Food and Drug Administration emphasized only the most severe hazards connected with the COVID-19 vaccination.

The National Institutes of Health, too, worked quickly to put the plan together. However, it would typically take years for funding for such a study to be approved.

“We were worried this was contributing to vaccine hesitancy in reproductive-age women,” said Bianchi.