Does the COVID-19 Vaccine Alter Menstrual Cycles?

It is well known now. Receiving the COVID vaccine may result in a set of clearly defined side effects including fever, chills, pain at the injection site, digestive problems, and headaches. We also know that these side effects can be particularly strong in people under age 55. This is an expected factor of stimulating the immune system to create immunity. More robust immunity leads to a more robust immune system response.

However, people are reporting other side effects. Since the early days of the COVID pandemic, women have reported changes to their menstrual cycles from the virus. The reports include changes such as more frequent, heavier flow, and more menstrual pain. Some women experience skipped periods.

In the same way, women who have received the COVID-19 vaccine also have reported similar changes like heavier periods, delayed periods, and more than one period during the first month after receiving the vaccine.

Since we know the vaccines affect immunity, and immune responses are also related to our menstrual cycles, it’s not a far leap to suspect that COVID vaccination could affect the menstrual cycle. Hypotheses suggest a variety of possible immune-mediated mechanisms are triggered by vaccination. These mechanisms may also impact menstruation and include: increased inflammation, nitric oxide production, mast cell activation, or toll-like receptor (TLR) signaling. These mechanisms can trigger changes in the uterine arteries and uterine lining, leading to increased uterine cramping and bleeding.

But, do COVID-19 vaccines cause changes in a woman’s menstrual cycle? A new study has provided data that suggests some good news.