With more of us getting vaccinated, there continues to be no evidence of problematic outcomes with fertility, or pregnancy, associated with Covid-19 vaccination.

But, I am definitely seeing enough patients experience changes to their menstrual cycle after vaccination, to pay attention.

In clinic I'm mostly seeing a delay in menstruation occurring (a longer cycle / later period) and/or a heavier bleed. This seems to be short-lived, lasting only a cycle.

This observation, being echoed around the world, was unexpected, and therefore highlights  a real gender-gap in the research about the Covid vaccines specifically, and in health-research in general.

Why is it so easy for research to dismiss the menstrual cycle?

Participants in Covid-19 vaccination trials weren't asked about any observed changes to their menstrual cycle, so this wasn't picked up and passed on as a potential reaction to Covid-19 vaccination.

Women have therefore been caught by surprise by any menstrual irregularities occurring after vaccination.

However menstrual irregularities do occur anyway, to all of us. Our body will occasionally throw out a long or short cycle, or a heavier / lighter bleed.

Usually menstrual disruption will be due to stress, infection, a change in diet, weight loss or gain, and a change in exercise habits. Um...global pandemic anyone...?!

And some of us will be regularly-irregular anyway, which in turn causes fluctuations in menstrual bleeding patterns.

So all this makes it hard to be able to directly attribute any menstrual irregularities to Covid-19 vaccination.

But...a lot of women are noticing a temporary change to their cycles. After their vaccination.

The menstrual cycle is viewed as a Vital Sign - a genuine marker of a woman's broader health picture.  So if menstrual irregularities are due to vaccination, it does prompt the question...why?

Researchers just don't know yet.

Some hypotheses are:

☾ if a woman has an underlying bleeding or clotting disorder, or has had issues with this in the past, that might predispose her to bleeding changes post-vaccine

☾ some women might have a more vascular uterine lining, predisposing her to post-vaccine bleeding changes

☾ perhaps there are as yet underlying and unknown autoimmune factors that might contribute to menstrual changes

☾ possibly an inflammatory response from the vaccine interferes with the normal inflammatory events that contribute to ovulation and menstruation

☾ potentially the immune cells that play a role in the growth and breakdown of the endometrial lining are affected by the vaccine

Researcher Dr. Kathryn Clancy, who experienced menstrual changes herself after Covid-19 vaccination is conducting an online survey to further analyse these experiences. If you've had your vaccine, do consider becoming part of this body of research! - join in here.

And if you haven't had your vaccine yet, know that you might experience a delayed period or a heavier period after your vaccination, and that this will be a short-lived change - like your sore arm or fatigue.

✴︎ Research about Covid vaccination and IVF here

✴︎ Research about Covid vaccination and fertility here and here 

✴︎ Research about Covid vaccination and pregnancy here

If you have any questions about Covid-19 vaccination and your fertility, please make an appointment with Jacintha to discuss

While you’re here you might also be interested in:

• my article Why you should consider detoxing before pregnancy

• my article Everything you need to know about coming off the Pill to conceive

• a free meal planner to keep you on track with your healthy eating goals

References

American College of Obstetricians and Gynecologists. Menstruation in girls and adolescents: using the menstrual cycle as a vital sign. Committee Opinion No. 651. Obstet Gynecol 2015;126:e143–6.

Berbic M & Fraser IS, Immunology of normal and abnormal menstruation, Review, Women's Health 2013, 9(4) 387-395

Cohut M, Can COVID-19 vaccines affect periods?, Medical News Today, 2021 July 21, https://www.medicalnewstoday.com/articles/can-covid-19-vaccines-affect-periods

Jimenez D, Covid-19 vaccines and periods: what do we know so far?, Pharmaceutical Technology, 2021 July 13, https://www.pharmaceutical-technology.com/features/covid-19-vaccines-periods-menstrual/

Jing Y et al, Potential influence of COVID-19/ACE2 on the female reproductive system, Molecular human reproduction, 2020, 26(6), DOI:10.1093/molehr/gaaa030

Sharp G et al, The COVID-19 pandemic and the menstrual cycle: research gaps and opportunities, OSF Preprints, 2021 June 8, DOI:10.31219/osf.io/fxygt

Sriram K, Insel P & Loomba R, What is the ACE2 receptor, how is it connected to coronavirus and why might it be key to treating COVID-19? The experts explain, The Conversation, 2021 May 14, https://theconversation.com/what-is-the-ace2-receptor-how-is-it-connected-to-coronavirus-and-why-might-it-be-key-to-treating-covid-19-the-experts-explain-136928

I love talking about all this stuff, all the time! Stay connected.