May 5, 2023 – There is not any evidence that COVID-19 vaccines cause disruptions to women’s menstrual cycles, based on a study of nearly 3 million women in Sweden.
The study was based on quite a few individual reports from women who stated that they'd noticed changes of their cycle after the vaccination, comparable to shorter days between periods or heavier bleeding.
The researchers observed an increased risk of postmenopausal bleeding after a 3rd vaccination dose.
The authors noted that “menstrual cycles naturally vary and minor menstrual disturbances are generally not considered clinically significant. However, changes can cause significant distress to affected women, particularly during a mass vaccination campaign when concerns are raised about adverse reactions that may not yet be well characterized.”
The Swedish study is probably the most comprehensive study thus far to search for a connection between vaccinations and menstrual changes. However, the researchers found no evidence that the injections are the cause.
The Results were published in the present issue of the Journal of the British Medical Association. The BMJ. From December 2020 to February 2022, data from women in Sweden aged 12 to 74 were analyzed. More than 2.5 million of the two.9 million women within the study received no less than one dose of a COVID-19 vaccine from Pfizer, Moderna or AstraZeneca. More than half of the ladies received three doses. Using data from visits to primary care or specialists, in addition to hospital stays, the researchers assessed the results of the vaccines inside 1 to 7 days after vaccination and inside 8 to 90 days. They searched for menstrual disorders comparable to a change in cycle days, unusual bleeding and postmenopausal bleeding.
The researchers said that while they found “weak and inconsistent associations” between vaccination and healthcare contacts related to menstrual changes and postmenopausal bleeding, they didn't find patterns strong enough to conclude that the vaccinations caused the issues.