EU Drug Regulator Recommends Adding ‘Heavy Menstrual Bleeding’ as mRNA COVID-19 Vaccine Side-Effect

A medic prepares a dose of the Pfizer-BioNTech COVID-19 vaccine in Netanya, Israel on Jan. 5, 2022. (Jack Guez/AFP via Getty Images)

The European Union’s drug regulator on Friday said it is recommending adding “heavy menstrual bleeding” as a side effect to both Pfizer’s and Moderna’s COVID-19 vaccines, according to an advisory panel meeting.

The European Medicines Agency’s (EMA) safety committee said that “heavy menstrual bleeding should be added to the product information as a side effect of unknown frequency of the mRNA COVID-19 vaccines Comirnaty and Spikevax,” referring to the Pfizer and Moderna shots.

It defines heavy menstrual bleeding, or heavy periods, as bleeding characterized by more volume or duration that “interferes with the person’s physical, social, emotional, and material quality of life,” noting that “cases of heavy menstrual bleeding have been reported after the first, second, and booster doses of Comirnaty and Spikevax.”

“Menstrual disorders in general are quite common and they can occur for a wide range of reasons,” it said. “This includes some underlying medical conditions. Any person who experiences postmenopausal bleeding or is concerned about a change in menstruation should consult their doctor.”

The panel said it has found no evidence showing that COVID-19 vaccine-linked menstrual disorders impacted fertility or reproduction. The EMA said that a review showed that the vaccines don’t cause pregnancy complications for pregnant women or their fetuses.

“The Committee reiterates that the totality of data available confirms that the benefits of these vaccines greatly outweigh the risks,” the EMA said.

Studies

This year, several studies have established a link between the COVID-19 vaccines and a change in menstrual cycles.

“Our findings are reassuring; we find no population-level clinically meaningful change in menstrual cycle length associated with COVID19 vaccination. Our findings support and help explain the self-reports of changes in cycle length. Individuals receiving two COVID-19 vaccine doses in a single cycle do appear to experience a longer but temporary cycle length change,” Dr. Alison Edelman of the Oregon Health & Science University and other researchers wrote earlier this year.

While the study did not find vaccination associated with changes in the length of periods, the researchers said their findings raise questions “about other possible changes in menstrual cycles, such as menstrual symptoms, unscheduled bleeding, and changes in the quality and quantity of menstrual bleeding.”

In September, a study published in the British Medical Journal by the same group of researchers evaluated about 20,000 vaccinated and 5,000 unvaccinated women around the world, obtaining their data from a period-tracking app called Natural Cycles.

The vaccine, they again found, can change or extend the menstrual cycle. Women who got the shot experienced approximately a one-day delay in getting their periods, compared with women who did not get vaccinated.

Zachary Stieber contributed to this report.