Is It Possible to Have Irregular Periods After COVID19 Vaccination

COVID vaccine and irregular periods

Women around the world are reporting irregular periods after COVID19

The 43-year-old woman, after her second dose of Moderna COVID19 vaccination, complained of heavy menstrual bleeding. She got the bleeding even though she hadn’t had any periods for over a year and a half due to Mirena IUD.

Initially, she did not link her heavy periods with the COVID19 vaccination until she saw other women with similar complaints on a Twitter thread.
One Twitter user reported having periods 3 weeks after the second shot of COVID19 vaccination although she hasn’t had any periods for the past couple of years.

Katharine Lee, a postdoctoral research scholar at Washington University School of Medicine, working on the survey to catalogue women’s menstrual experiences after receiving the COVID-19 vaccine said:

“While the study will look at trends, they won’t be able to determine cause and effect. Our survey cannot tell us anything about the prevalence or the number of people who are affected. What we can do is look for associations and trends that help us direct whatever the next study would be.”

Some physicians, scientists, and researchers are eager to find the link between the COVID19 vaccination and the menstrual irregularities, while others believe that the irregularities can be due to the stress hovering over individuals during the pandemic and specifically to the stress related to the vaccination.

Postmenopausal women are also reporting having episodes of bleeding after the COVID19 vaccination, therefore, it has raised concerns regarding a physical relationship between the two. However, the relationship and the link are yet unproven.

The lining of the uterus is part of the immune system of the body. It is safe to say that immune cells play a vital role in the growth of the endometrial cells, their regeneration, and shedding. Since the COVID19 vaccine, with its chemicals, has the potential to affect the immune system, this may be leading to the shedding of the endometrial lining, hence the spotting and bleeding. However, this is just a potential explanation/theory which has not been proven yet.

Dr. Jerilynn Prior, professor of endocrinology at the University of British Columbia and Scientific Director of the Center for Menstrual Cycle and Ovulation Research, thinks that the link between menstrual irregularity and the COVID19 vaccine is highly unlikely.

Dr. Julie Levitt, an OB-GYN at Northwestern Medicine, reported two patients with irregular menstrual periods after the COVID19 vaccine. She said:

“Bleeding occurs for so many reasons that it’s really hard to isolate the two. A hormone rises, it goes down, you bleed a withdrawal bleed. But is that a bad thing? No!
No. 1, I wouldn’t worry. No. 2, contact your doctor if you want to talk about it to gain that reassurance. If it does continue after a few weeks following the administration of the vaccine, it probably is something else.”

With the bleeding occurring after the vaccine, there is another concern: Can the COVID19 vaccine lead to pregnancy loss as it has the potential to cause bleeding?
No, the COVID19 vaccine doesn’t add to the risk of miscarriage. There is no evidence or reports of pregnancy loss with the vaccination.

Dr. Alexandra at the University of Oxford explained that the periods’ irregularity can be due to the inflammatory response of the body to the vaccine, nothing more than that. Moreover, these effects are temporary too.

Some individuals even started the propaganda that women who haven’t been vaccinated yet may have menstrual irregularity by just being near people who were vaccinated. However, such claims are false and raise suspicion of anti-vaccine conspiracy.

Bottom line:
Although women are reporting irregular periods, scientists and researchers have clarified that this should not stop women from getting the vaccines as there is no establish link yet. Besides, even if there is a connection, this effect is temporary with no long-term complications.


STOCK, N. (2021, April 20). Some people are reporting abnormal periods after a COVID-19 vaccine. U. of I. professor is looking for answers. Retrieved from CHICAGO TRIBUNE:

Taylor, B. (2021, April 16). Menstrual changes to be expected after COVID-19 vaccine, during a pandemic: experts. Retrieved from CTV news:

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Dr. Arsia Hanif has been a meritorious Healthcare professional with a proven track record throughout her academic life securing first position in her MCAT examination and then, in 2017, she successfully completed her Bachelors of Medicine and Surgery from Dow University of Health Sciences. She has had the opportunity to apply her theoretical knowledge to the real-life scenarios, as a House Officer (HO) serving at Civil Hospital. Whilst working at the Civil Hospital, she discovered that nothing satisfies her more than helping other humans in need and since then has made a commitment to implement her expertise in the field of medicine to cure the sick and regain the state of health and well-being. Being a Doctor is exactly what you’d think it’s like. She is the colleague at work that everyone wants to know but nobody wants to be. If you want to get something done, you approach her – everyone knows that! She is currently studying with Medical Council of Canada and aspires to be a leading Neurologist someday. Alongside, she has taken up medical writing to exercise her skills of delivering comprehensible version of the otherwise difficult medical literature. Her breaks comprise either of swimming, volunteering services at a Medical Camp or spending time with family.


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