COVID Vaccine Impact Menstrual Cycle of Women, Study Says

Researchers now add temporary menstrual changes as one of the side effects of getting a COVID vaccine shot.

According to Science Advances, 42 percent of people with regular menstrual cycles said they bled more heavily after vaccination. Forty-four percent said they noted no changes in their menstrual bleeding, while 14% reported a lighter period. Meanwhile, women who have menopaused or are using long-term contraceptives reported that many experienced breakthrough or unexpected bleeding after their COVID vaccination.

The research author noted that the percentages do not represent the rate of menstrual changes in the general population since only people who emphasized the difference in the menstrual cycle were more likely to participate, NBC News.

Changes in the menstrual cycle

The study involved more than 39,000 people 18 to 80 years old who were fully vaccinated and had not contracted COVID. The survey hoped to provide evidence for future studies, not establish cause and effect.

The survey started on April 2021, when women reported unexpected bleeding and heavier bleeding after COVID vaccination. Health experts often met the anecdotes with a rebuttal that no data links menstrual changes to immunization.

The study co-author, Katherine M.N. Lee, said that overwhelming responses from women inspired her and her colleagues to conduct a study about their menstrual cycle.

Lee said that after her COVID shots, she noted that she had the worst menstrual cramps in her life. Her friend, Kathryn Clancy, a biological anthropologist at the University of Illinois, Urbana-Champaign, said she had menstrual flooding after her first dose. According to Science.org, Clancy posted her experience on Twitter, and she got an overwhelming response saying that they too had changes in the menstrual cycle after their COVID shots.

Candace Tingen, a program director of the National Institute of Child Health and Human Development, said that data on the relationship between COVID vaccination and menstruation was nil when the vaccinations came out.

Companies barely assessed the direct effect of vaccination on the menstrual cycle, and most pharmaceutical trials did not include questions about menstruation. Tingen thinks that if COVID 19 vaccine trials had asked about menstruation, people might not have been as surprised by the unexpected side effect.

The study participants were vaccinated with Astra Zeneca, Johnson and Johnson, Moderna, Pfizer, and Novavax.

Menstrual cycle reports from the U.K.

In Great Britain, the Medicines and Healthcare Products Regulatory Agency (MHRA) said that their agency got 34,633 menstrual and vaginal bleeding reactions reports after the COVID-19 vaccine from December 8, 2020, and September 8, 2021, Healthline says.

The reports include delayed periods, bleeding between periods, vaginal bleeding after menopause, and heavier menstrual bleeding.

Women who had the Pfizer-BioNTech vaccine and the AstraZeneca vaccine reported the symptoms as women who had the Pfizer-BioNTech vaccine and the AstraZeneca vaccine. MHRA noted that no evidence suggests that COVID 19 vaccine had an effect on fertility.

MHRA said changes in the menstrual period after vaccination might be because of the body's response to the vaccination in general, rather than the component or ingredient of the vaccine.