Menstrual changes after the Covid-19 vaccine
According to a renowned immunologist specializing in fertility, menstrual changes and unexpected vaginal bleeding after administration of the Covid vaccine should be investigated to reassure women.
Your Period May Change After a Covid-19 Vaccine: A Gynecologist's Explanation
These include heavier than usual periods, late periods, and unexpected bleeding after receiving the vaccine.
Menstrual disorders are extremely common, they can be caused by many different factors, and the number of women affected is low, she says.
Some women have also reported period changes after infection with the virus or after a prolonged period of Covid.
Counteract misinformation and reassure
However, in an opinion piece published in the BMJ, Dr. Male states that "solid research" on reports of menstrual problems would help counter misinformation about vaccines.
"Young women's reluctance to get vaccinated is largely due to false claims that Covid-19 vaccines could harm their chances of future pregnancies."
"Not thoroughly investigating reports of menstrual changes after vaccination is likely to fuel these fears."
"If a link between vaccination and menstrual changes is confirmed, this information will allow people to predict potentially disturbed cycles," she added.
Dr. Male, Senior Lecturer in Reproductive Immunology, said "clear and reliable information" is important for women who are confident in the ability to predict their cycles.
There are no definitive explanations yet
Scientists don't yet understand exactly how vaccines can cause period changes. They may be related to the impact of the immune system, which is reinforced by the vaccine, on the hormones that govern the menstrual cycle, but could also be caused by immune cells that act differently on the lining of the uterus.
Other vaccines, such as the HPV vaccine, have also been linked to similar menstrual changes, but little research has been done on the why and how of these phenomena.
Scientists agree that a woman's ability to have a baby is not affected by vaccines. Trials show that vaccination did not affect a woman's chances of getting pregnant naturally or during fertility treatment. Research on male fertility after vaccination also shows no impact on sperm quality.
Dr Jo Mountfield, vice president of the Royal College of Obstetricians and Gynecologists (RCOG), said rule changes can be worrisome, but generally only last one or two cycles.
He encouraged anyone experiencing unusual heavy bleeding, especially after menopause, to seek medical advice, but emphasized that there is no risk of long-term harm.