Why The Covid Vaccine Might Impact Your Periods

You might experience a heavier period – but don't panic.

Almost 4,000 women have reported changes to their periods following the Covid-19 vaccine, but doctors want to reassure women this isn’t something to worry about.

The Medicines & Healthcare products Regulatory Agency (MHRA) received a total of 3,958 reports of changed periods, up to the date May 17, according to data obtained by The Times. The majority of reports were about “heavier than usual bleeding”.

But Dr Nighat Arif, a GP specialising in women’s health and family planning, tells HuffPost UK these changes are temporary and shouldn’t deter women from having the vaccine. “After millions of doses of the vaccine being given across the globe, there’s no evidence the Covid-19 vaccine causes long-term problems with your periods and it does not affect your fertility,” she says.

“It’s important to understand that the lining of the womb is where the immune system sits. So, just like having a temperature, a headache, aches and pains is a side effect of any vaccine because it triggers the immune system – the same immune response happens in the womb lining.”

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You might experience an irregular period, a heavy period or a missed period after the vaccine due to the immune response, but this is temporary, she adds.

“Our cycles vary due to so many factors such as stress, diet, weight changes but actually, catching Covid-19 has a very good chance of messing with your menstrual cycle, so the best way to protect your overall health and your cycles is to get vaccinated,” she says.

Other leading doctors have urged women not to panic at reports of altered periods. “It’s important to remember these side effects are mild and shouldn’t deter women from having the vaccine,” said Dr Pat O’Brien, vice president at the Royal College of Obstetricians and Gynaecologists (RCOG).

“Many women will experience a temporary change in their periods from time to time during their lives. And right now, many women in their 20s and 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.”

Dr O’Brien reiterated there is no evidence to suggest Covid-19 vaccines will affect fertility. The RCOG said it supports more data collection in this area to understand more about the vaccine and perceived changes in menstrual cycles.

You can report any suspected side effects of the vaccines, as well as any medicines, via the ‘yellow card’ system, here.