Can COVID-19 infection or vaccination affect periods?

Health & Wellness Reproductive Health

A: Maybe. Period changes after you get the COVID-19 vaccine or are sick with COVID-19 are possible, but do not last long. Period changes lasting more than a few cycles should be reported to your health clinician.

Anything that might affect hormonal balance, uterine lining, or your ovaries may cause a change in your menstrual cycle. It is normal for the timing of your period to change by a few days from month to month. A LOT of things can affect periods, which may include the COVID-19 vaccine or COVID-19 infection. Any changes to your period after COVID-19 infection or vaccination infection are likely due to your body’s immune response and are temporary.

Things that may cause changes in your period include:


😑Low mood

⭐Weight changes


💤Lack of sleep


🤰 Pregnancy/Lactation

💊Starting new birth control

⚕️Changes in medicines

🏋️Strenuous exercise

💉COVID-19 Vaccine

🤒COVID-19 Infection

🤒Any infection

The COVID-19 pandemic has altered many routines such as exercise, sleep, and diet while also causing lots of stress. These reasons and others may be behind reports from many people who described their cycles being shorter apart, bleeding for a shorter time, having a smaller amount of blood, longer cycles, heavier periods, or more painful periods during the COVID-19 pandemic. In addition, the immune response from COVID-19 infection or vaccine can cause inflammation. Inflammation can change hormone levels or the lining of the uterus. The hormone changes could then result in temporary changes to your period.

People have reported missing periods, bleeding between periods, longer cycles, shorter cycles, heavier bleeding, or less bleeding after having COVID-19 or the vaccination. Almost all people reported their periods returning to normal within a few months after infection. The design of existing studies makes it difficult to determine how often period changes occur after COVID-19 vaccination or infection because there is often not a comparison group to know the typical level of menstrual changes even without a COVID-19 infection or vaccination.

A recent paper looked at changes before and after vaccination in people using a period tracking app (link below). Vaccinated people had slightly longer cycles (less than a day) compared to unvaccinated people, but the length of periods was the same. Within one cycle after vaccination there were no differences between the vaccinated and unvaccinated. Period changes were not measured in the original vaccine randomized trials, which would have provided the best evidence.


Many things can alter menstrual cycles, including COVID-19 infections or vaccinations. Most people do not notice any changes. For those who do, changes typically resolve within a few months. If you have missed your period and could be pregnant, consider taking a pregnancy test. If you miss or experience changes in your period for more than three months, give your healthcare clinician a call.

Thanks to JD in New Hampshire for the question!

Stay safe. Stay well.