Do COVID Vaccines Cause Menstrual Changes? NIH Awards $1.67 Million in Grants to Study Possible Link
Five institutions will explore potential links between COVID vaccines and menstrual irregularities — research that wasn’t conducted during clinical trials, but is being done now, after thousands of women reported changes in their menstrual cycles post vaccination.
The National Institutes of Health (NIH) has awarded one-year supplemental grants totaling $1.67 million to five institutions to explore potential links between COVID vaccines and menstrual changes, after thousands of women reported menstrual irregularities after vaccination. According to the NIH website, some women have reported experiencing irregular or missing menstrual periods, heavier-than-usual bleeding and other menstrual changes after receiving COVID vaccines. The new funding will go toward research to determine whether the changes may be linked to COVID vaccination itself, and how long the changes last. Researchers will also seek to clarify the mechanisms underlying potential vaccine-related menstrual changes. The year-long study will initially follow unvaccinated participants to observe changes that occur following each dose. Some groups will exclude participants on birth control or gender-affirming hormones, which may have their own impact on periods. Researchers will assess the prevalence and severity of post-vaccination changes to menstrual characteristics, including flow, cycle length, pain and other symptoms. These analyses will account for other factors that can affect menstruation — such as stress, medications and exercise — to determine whether the changes are attributable to vaccination. The five NIH-funded studies will be conducted by researchers at Boston University, Harvard Medical School, Johns Hopkins University, Michigan State University and Oregon Health and Science University.
The studies will likely incorporate between 400,000 and 500,000 participants –– including adolescents and transgender and nonbinary people, according to Dr. Diana Bianchi, director of the agency’s Institute of Child Health and Human Development, which is funding the research along with NIH’s Office of Research on Women’s Health. “Nobody expected it [vaccination] to affect the menstrual system, because the information wasn’t being collected in the early vaccine studies,” said Bianchi, who credited The Washington Post’s early coverage of the issue, in April, with first making her and her staff aware of it.
These “rigorous scientific studies will improve our understanding of the potential effects of COVID-19 vaccines on menstruation, giving people who menstruate more information about what to expect after vaccination and potentially reducing vaccine hesitancy,” Bianchi added. So far, no published studies have examined — or offered conclusive evidence — of possible links between the vaccines and menstruation.
The COVID vaccine trials did not specifically ask participants whether they saw adverse side effects in their menstrual cycles or volumes — an omission Bianchi attributes to the fact “the Emergency Use Authorization was really focused on critical safety issues” and “changes to your menstrual cycle is really not a life and death issue.”
But the lack of formal research on the potential link between the two “points out the fact that safety studies for vaccines … are not necessarily thinking about the reproductive health of women,” Bianchi said. “We hope one of the things that’s going to come out of this is that questions will be added to clinical trial studies to include any changes in menstrual health.” According to the NIH, numerous factors can cause temporary changes in the menstrual cycle, which is regulated by complex interactions between the body’s tissues, cells and hormones. Immune responses to a COVID vaccine could affect the interplay between immune cells and signals in the uterus, leading to temporary changes in the menstrual cycle. Menstrual changes after COVID vaccination also could be attributed to immune responses to the vaccines and their impacts on the uterus, as well as to pandemic-related stress, lifestyle changes and the virus itself.
The new studies will build on existing research and leverage data from menstrual tracking applications to evaluate the potential impacts of COVID vaccination on menstrual health among geographically and racially and ethnically diverse populations.
The researchers hope that, following a peer-review process, findings will be published by the end of 2022 or soon after. As The Defender reported, researchers have called for clinical trials since April to track and document menstrual changes in vaccinated women after some women reported hemorrhagic bleeding with clots, delayed or absent periods, sudden pre-menopausal symptoms, month-long periods and heavy irregular bleeding after being vaccinated with one or both doses of a COVID vaccine