Since 2021, when widespread COVID-19 vaccinations began, multiple cases of women with painful cramps, delayed periods and other changes in their menstrual cycles were reported. Right away, researchers looked into the matter and found a correlation between the COVID-19 shots and menstrual cycles.
But how do COVID-19 vaccinations affect the menstrual cycle and how severe are the symptoms?
What Is the Menstrual Cycle?
The monthly set of changes that a woman’s body goes through in preparation for a potential pregnancy is known as the menstrual cycle. The ovaries release an egg once a month in a process called ovulation. If ovulation occurs but the egg is not fertilized, the uterine lining sheds via the vaginal opening. This is the start of a menstrual cycle. As a female, you can track your start date and end date every month of your menstrual cycle.
COVID-19 Vaccine on Menstrual Cycle: The Effects Are Temporary
Menstrual periods did shift after being vaccinated against COVID-19, according to a published study. The authors found that women had slightly longer menstrual periods after receiving the vaccination than those who were not. Some women reported late periods, while others reported heavier and painful bleeding. Some women who hadn’t had a period in years said they had menstruated again and reported exceptionally high flows and breakthrough bleeding.
The COVID-19 immunization can alter menstrual cycle timing. However, women’s minds should be at ease; the side effects are temporary, similar to a sore arm rather than a significant adverse occurrence, and shouldn’t deter women from getting vaccinated.
The Relationship between the Immune System and the Reproductive System
Medical experts are still baffled as to why the menstrual alterations occur. Some researchers pointed towards the link between the immune system and the reproductive system as the primary cause. Given this link, it’s likely that stimulating the immune system through vaccination could alter a person’s cycles, though only for a short time.
Each human body organ belongs to 1 of 10 human body systems: circulatory, respiratory, nervous, muscular, skeletal, digestive, endocrine, immune or lymphatic, integumentary and reproductive. These body systems are intertwined and work together to maintain internal stability and equilibrium, often known as homeostasis. However, homeostasis can be disrupted by disease in one body system, causing problems in other bodily systems.
For example, if you contract the AIDS virus, which damages your immune system, you may develop pneumonia in your lungs and a yeast infection in your reproductive system.
What Does the Research at Oregon Health and Science University Say?
The Oregon Health and Science University researchers in Portland, led by Alison Edelman, analyzed anonymized data from thousands of women who used the Natural Cycles fertility tracking app to record details about their menstrual cycles regularly. 2,403 of the 3,959 women who took part in the study were vaccinated, while 1,556 were not. The majority of people received Pfizer or Moderna vaccinations.
Women who got one dose of COVID-19 vaccination during a single menstrual cycle experienced a slight increase in cycle length of just over half a day on average. Those who received two vaccine doses during the same menstrual cycle had a two-day increase in cycle duration, while 10% of these women had a cycle length shift of eight days or greater. However, these side effects were immediately restored to normal during the following cycles, indicating that they were just transient.
The researchers found no population-level clinically relevant change in menstrual cycle length linked with COVID-19 vaccination. The researchers noted that the rise they detected was within the range of normal fluctuation—most women wouldn’t notice if their period arrived half a day later than usual.
The findings confirmed that the COVID-19 vaccinations would have no significant impact on women’s menstrual cycles. There’s no reason to believe that such minor alterations in the menstrual cycle would impact fertility.
A Parting Reminder
The vaccination’s side effects on women are just temporary. No hard evidence has yet been established that vaccinations affect menstruation and fertility. So, ease your fears about menstrual cycles and the COVID-19 vaccine!