There’s been a whole heap of stuff about this in the media recently – mostly anecdotal reports from women saying they’ve experienced changes to their menstrual cycles following the jab. Along with the predictable sore arm, headaches, and general malaise that you get with any vaccine, women are reporting heavier or more painful periods. Some post-menopausal women and trans men who are taking hormones to suppress menstruation have even found themselves having periods where once there were none.

Doctors and scientists are weighing in with their opinions on a daily basis, but the truth is there hasn’t been enough time to do any quality research, so no one knows for sure whether it’s actually happening, or whether there might be a bunch of other reasons that are being lumped together, because everyone’s talking and reading about it.

But let’s say for argument’s sake that there is a physical reaction happening. Why would that happen and what does it mean?

Fact: The lining of the uterus is part and parcel of the immune system. Immune cells help to build up, maintain and break down this lining as part of the monthly cycle. Vaccinations have the potential to affect immune cells anywhere in the body, so it’s reasonable to assume they might make a difference to the uterus lining, too. (This doesn't mean there is any link to miscarriage, though – once the placenta is in place, the immune cells are ineffective here.)

The good news is that if you do experience a heavy or early period after the COVID vaccine, and the two things are in fact linked, then it’s only a temporary thing. There is evidence that the regular flu vaccine and the HPV vaccines can also affect the menstrual cycle temporarily, but not in the long term.

There have been calls for studies into the effect of the vaccine on periods, simply so that we know what to expect. Women, trans men and post-menopausal women should be aware of possible side effects so they don’t freak out when something weird happens to their cycle. (Side rant: If it was something that may or may not happen to men, you’d be placing a bet that it would have been fully looked into by now.)

The important thing here is to learn to disentangle the facts from the anti-vaccine and conspiracy rhetoric out there on social media. COVID vaccines are NOT part of a mass sterilisation plot, period. Be informed, be safe, and when the time comes, be vaccinated.