The most common side effects following COVID-19 vaccines are fatigue, a fever, headaches, body aches, chills, nausea, diarrhoea, and pain at the site of injection, according to the World Health Organization. There have also been reports of more uncommon side effects of the vaccine including worrying cases of blood clots. Some women have reported heavier than usual periods, late periods, breakthrough bleeding, or more painful cramps. For some, a combination of all.
Gynaecologist Dr Jen Gunter posted an article on social media which said: “There are an increasing number of reports surfacing online of changes in the menstrual cycle shortly after the Covid vaccination, either bleeding that appeared earlier than expected (a few days after the vaccine), was heavier than expected, and/or more painful than expected.
“The impact of vaccines on menstruation isn’t typically tracked in studies.
“Bleeding that is heavy enough to require a trip to the emergency room would be picked up in most vaccine studies, but not an early period, breakthrough bleeding, a heavier period, or a more painful one. This lack of information is maddening.
“My hypothesis is that it is an immune response in the endometrium (which is part of the immune system).”
Dr Akshat Jain, a hematologist at Loma University School of Medicine explained: “Inflammatory reaction has been noticed with the Covid vaccine.
“We know that because many, including myself after the second vaccine, developed some mild flu like symptoms.
“That inflammation has a potential or potentially can modulate oestrogen response, which could be the link between certain women having heavy periods after the vaccine.”
Dr Jain specializes in bleeding disorders in adolescent women and explained that inflammatory cells triggered by the vaccine could affect hormones.
According to Dr Alexandra Alvergne at the University of Oxford there was a plausible link between the vaccine and menstrual changes.
A large part of this could come down to the timing of ovulation (when an egg is released) which can be affected by inflammation.
Scientists have recently developed a survey to better understand how many women may be affected by the vaccine and period changes.
The findings won’t determine whether there’s a relationship between COVID-19 vaccines and menstrual changes, but could help form the basis for further research, said Katharine Lee, one of the researchers, who is based at Washington University in St. Louis.
Period irregularities can be triggered by a variety of normal events including diet changes, stress, overexercising, taking medications like birth control and steroids, or even poor sleep.
There are also a variety of serious, underlying medical conditions which could play a role, too, including endometriosis, pelvic inflammatory disease, polycystic ovary syndrome, or uterine fibroids.
Doctors and health experts strongly recommend if any women are experiencing heavy bleeding, they should see their doctor for a complete blood count and oestrogen test.