There have been a lot of whisperings with people noticing their period is a bit late, or a bit heavier than usual over the past few months. Have you thought about connecting the changes to a covid-19 infection or the vaccine?
Here are the facts as they stand right now:
Both have been linked, although the evidence isn’t conclusive just yet.
Does COVID-19 infection affect menstrual cycles?
- Menstrual cycle changes after covid-19 have been reported, including heavier, more irregular periods or unscheduled bleeding
- Even in those without proven Covid-19, studies looking into menstrual cycle change have shown more cases of menstrual disturbance compared to pre-pandemic.
- An international study of long-COVID showed 1 in 3 reported new menstrual issues.
- It remains unclear whether reported changes are due to COVID-19 infection or other pandemic related factors, such as psychological stress or behaviour change.
Does the COVID-19 vaccine affect menstrual cycles?
Possibly, yes.
Anecdotally there have been reports that people who menstruate have noticed changes to their cycle in the first 1-2 months after a dose of the Covid-19 vaccine. The changes are similar to those after having the covid-19 infection
- Heavier than usual bleeding
- Delayed periods
- Unexpected vaginal bleeding.
However, so far in these reports there is no suggestion of any longer-term changes and the vast majority of people find their cycles return to normal quickly.
How could the COVID-19 vaccine affect menstrual cycles?
We don’t fully know yet as the research is still being collected.
It is possible that the immune response your body makes in response to the vaccine can disrupt the production of sex hormones (just like when you are stressed or exercise too much).
The immune response can also impact the lining of the womb (endometrium) which leads to the changes in bleeding pattern you may see.
We expect these changes to be temporary, just like many factors that change throughout someone’s life which impact their periods at different times.
If my menstrual cycle is affected, what happens to fertility?
- There is no evidence that the Covid-19 vaccine can have any lasting impact on fertility.
- We have seen from past vaccine surveillance reports of previous vaccines (eg HPV) that other vaccines also temporarily affect the menstrual cycle.
- We do not yet know if the vaccine is definitely linked to menstrual changes either; other factors such as stress, exercise and nutrition can affect menstruation and it can be hard to draw a through-line of cause and effect between vaccination and menstrual cycle changes.
- If you plan to get the vaccine, this shouldn’t put you off!
References
- Li, Kezhen et al. “Analysis of sex hormones and menstruation in COVID-19 women of child-bearing age.” Reproductive biomedicine online vol. 42,1 (2021): 260-267. doi:10.1016/j.rbmo.2020.09.020
- Davis, H et al., Characterizing Long COVID in an International Cohort: 7 Months of Symptoms and Their Impact. (2020)Available at SSRN: https://ssrn.com/abstract=382056
- Phelan N, Behan LA, Owens L. The Impact of the COVID-19 Pandemic on Women’s Reproductive Health. Front Endocrinol (Lausanne). (2021). doi: 10.3389/fendo.2021.642755.
- Suzuki S, Hosono A. No association between HPV vaccine and reported post-vaccination symptoms in Japanese young women: Results of the Nagoya study. Papillomavirus Res. 2018 Jun;5:96-103. doi: 10.1016/j.pvr.2018.02.002.
- British Fertility Society and Association of Reproductive and Clinical Scientists. Covid-19 vaccines and fertility. 8 February 2021 [https://www.britishfertilitysociety.org.uk/2021/02/09/ bfs-arcs-covid-19-vaccines-fertility/]. Accessed 11 July 2021.