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RCOG responds to reports that COVID-19 vaccine affects periods

News 18 May 2021

The RCOG brought out a new statement on the 16 September 2021.
This statement was updated on 28 May 2021 to include an additional quote from Dr Pat O'Brien.

The RCOG is aware there have been anecdotal accounts from people who say they've experienced changes to their menstrual cycle after having the COVID-19 vaccine.

This BBC article highlights the issue and explores the possible causes.

Commenting on this, Dr Sue Ward, Vice President at the Royal College of Obstetricians and Gynaecologists, said:

“We’re aware some women have been reporting a change to their period cycle or symptoms during the pandemic. The degree to which changing hormone levels will affect someone is often informed by her psychological wellbeing at that time. We know that life events can make PMS symptoms feel worse and something as all-consuming and life-changing as a global pandemic could result in women experiencing their periods differently.

“Anecdotally some women seem to be reporting heavier periods after receiving the COVID-19 vaccine and we would support more data collection in this area to understand why this might be the case.”

“If you do notice any bleeding that is unusual for you, then we would recommend you contact your doctor.  You can also report any concerns or possible side effects of the COVID-19 vaccine here"

Dr Pat O’Brien, Vice President at the Royal College of Obstetricians and Gynaecologists, said:

"It’s important to remember these side effects are mild and should not deter women from having the vaccine when they are called. Many women will experience a temporary change in their periods from time to time during their lives. And right now, many women in their 30s are having the COVID vaccine. So it seems inevitable that in some women these two events will coincide by chance. If, however, these changes persist, or you have any new vaginal bleeding after the menopause, you should see your doctor.

 “We also want to stress that these perceived changes in menstrual cycle after having the COVID-19 vaccine should not be confused with an impact on fertility and the ability to have children. There is no evidence to suggest that COVID-19 vaccines will affect fertility.” 


To contact the RCOG press office call +44 (0)7986 183167 or email