Covid-19 vaccine and the menstrual cycle: What you need to know

    Published: 02 October 2021. Written by Tom Ward.

    Our expert explains this trending concern around the Covid-19 vaccine and the menstrual cycle, and why getting the Covid vaccine is the best way to safeguard your health.

     No, the Covid-19 vaccine doesn’t equip you with 5G trackers. And no, they aren’t likely to make your children grow three legs and two heads. But, like every single medication on the planet, they do come with a risk of side effects.

     And, although as yet unconfirmed by the Medicines and Healthcare products Regulatory Agency (MHRA), an increasing number of people who menstruate have reported changes to their cycle and/or unexpected vaginal bleeding in the days and weeks afterwards.

     Researchers have not established a formal link between the vaccines and menstrual cycle changes, but, reassuringly, the MHRA is in the process of studying the link between vaccination and menstrual changes.

     So, should you be worried?

     To put your mind at ease, we spoke with Dr Anushka Patchava, Deputy Chief Medical Officer at Vitality, and Dr Nitu Bajekal, a senior consultant obstetrician and gynaecologist, and Founder of Women for Women’s Health, a voluntary service set up to educate, energise and empower women to make healthy lifestyle choices.



    What are the side effects?

     Both Dr Patchava and Dr Bajekal are aware of the reports around altered menstrual cycles, but both advise this is likely to be mild, and nothing to worry about too much. Dr Bajekal explains that of the dozens of young patients she has seen since the pandemic, no one has reported ‘any significant concern’ with their periods.

     ‘Research is ongoing, but our knowledge from millions of women having already received the vaccine and other vaccines, is that there is no reason at all for avoiding the vaccine if someone is eligible, whatever their age,’ she explains.

     ‘Both Covid infection and vaccines for Covid may cause mild disturbance of menstrual cycles that last for a month or two,’ Dr Bajekal adds. ‘This is thought to be because the immune system and the sex hormones may be temporarily affected, in a similar way that stress or exercise does.’

    How common are these side effects?

     ‘Any medication is subject to side effects,’ Dr Patchava explains. ‘There are common side effects that are generally often short-lived and are seen across the general population. And there are less common or rare side effects. In the UK, the MHRA stays on top of these. All side effects are tracked and reported, and this is done even more critically when it’s a vaccine like this that has been developed at pace.’

     So, with the Covid vaccine you might experience sore arms, fatigue or a general mild flu sensation. As Dr Patchava explains, the MHRA is in charge of monitoring all side effects from any medication. It has set up a surveillance scheme to monitor reactions to all types of Covid vaccine, with primary care clinicians noticing reports of changes to periods and unexpected vaginal bleeding after having a vaccination.

    Is this unexpected?

     Dr Patchava estimates that there have been more than 30,000 reports of Covid vaccines interfering with menstrual cycles, with the Pfizer and AstraZeneca vaccines both linked to this. However, she isn’t worried, pointing to similar results from the human papillomavirus (HPV) vaccine in the past.

     ‘At present, scientists believe this is a result of an immune response to the virus rather than a result of a component of the virus itself,’ she explains. In other words, any menstrual interruption could be a result of your body adjusting to the vaccine (like when you change birth control, for example), rather than something harmful coming from the vaccine itself.


    How long will any changes last?

     The MHRA is still gathering data on this, but it seems that any changes do return to normal after around a month, with no evidence that the Covid-19 vaccine adversely affects fertility.

     ‘We can never definitely say with any vaccine that everyone will be OK,’ says Dr Patchava. ‘But, if you’re experiencing changes to your menstrual cycle that you believe are in relation to the vaccine – i.e. without other symptoms such as pain or other disturbances – my advice is to let your GP know as this helps the MHRA collect data, then watch and wait.’

     However, should any changes last longer than one or two cycles, Dr Patchava advises you seek clinician input in order to ensure there isn’t something else going on that just happened to coincide with your vaccination.

     ‘It’s especially important to have these open conversations if you’re pregnant or undergoing fertility treatment and are due to have the vaccination,’ Dr Patchava explains. ‘If you are in that situation, ask about your own personal risk as well as the best time to have the vaccination.’

    Should I still get the vaccine?

     Dr Bajekal advises that women and those assigned female at birth (AFAB) should indeed get both doses of the vaccine, if eligible. ‘The consequences of not having the vaccine and getting Covid far outweigh the tiny risks associated with the vaccine,’ she explains, pointing to the official advice from the Royal College of Obstetrics and Gynaecologists:

     ‘Women may wish to discuss the benefits and risks of having the vaccine with their healthcare professional and reach a joint decision based on individual circumstances. However, as for the non-pregnant population, pregnant women can receive a Covid-19 vaccine even if they have not had a discussion with a healthcare professional.’

     Dr Patchava is emphatic that getting the vaccine is the right choice, not just for you, but for those around you too. ‘In the majority of cases, vaccination is safe and effective. It is recommended and has been proven to prevent serious illness and hospital admission if you were to get infected,’ she stresses. ‘There is a social responsibility around vaccination to protect those around you and prevent the wider spread of Covid. Encouraging vaccination is probably the easiest way out of this pandemic.’

     In summary: the Covid vaccines are believed to be safe. Any changes to your menstrual cycle or excessive bleeding lasting one or two cycles most likely aren’t anything to worry about, but it’s always worth speaking to your healthcare provider if you’re concerned. And, as Dr Patchava says, while vaccination is your prerogative, it is the fastest way to ensure the health of yourself and those around you.

     Want to know more ways getting clued up on your menstrual cycle can change your life? Read more here.

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