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Pfizer vaccine & period?

43 replies

Twatalert · 06/04/2021 14:31


I had my first pfizer shot at the end of Feb and a normal period early March.

I'm now due again and have had a very unusual month!! I had no water retention in my legs, no cravings, in fact low appetite, no oily hair or skin as usual in the two weeks leading up to my period.

I have had period like cramps for two days now, although much lighter than usual. The thing is I don't bleed...there is only brown spotting which is very, very light. I'm waiting for the gush of blood....but maybe it won't come?

Could this be vaccine related?

It is very unusual for me to not come on like clockwork.

It's been great without any pms. This must be what men feel like? Each day is the same? Your body, hair and skin don't change every month? It's easy to stick to a diet too.

OP posts:
weegiepower · 06/04/2021 16:07

I had mine end of feb (Pfizer) and haven't even had a period since, so very late, have been incredibly hormonal since, bad craving, skin playing up, extra water retention...!

MaryLennoxsScowl · 06/04/2021 16:14

Yes, they do mean in the bloodstream causing strokes, but I thought it was interesting that it seemed to cause period blood to clot too - might be a warning sign?

EBearhug · 06/04/2021 16:18

I had Pfizer at the end of February and periods have been normal.

Georgieporgie29 · 06/04/2021 16:41

I had the az in feb. I’m on the pill so just have a withdrawal bleed. My next one wasn’t like normal, there was no actual red blood, just one day of brown (old blood). I thought it was strange but just kind of assumed it’s due to my age - I’m the wrong side of 40 - but I noticed a different thread around that time about the same thing and did wonder if it could be connected. Now reading this thread it makes me even more curious. 2nd break this week so will be interesting if it’s the same or if I get 2 months worth!

ColdandFrosty1 · 06/04/2021 17:25


Had jab on Friday, period started on Sunday as expected.

Having the jab will make no difference to your menstrual cycle - they are completely different bodily systems. Stressing about the vaccine, however, may have an effect.

So many different bodily systems cause different symptoms within each other so it could have an effect for all we know
AgentCooper · 06/04/2021 17:30

Covid made my period start 5 days early, stop completely then come 10 days late. So I don’t think it’s out of the question that the vaccine could affect it.

Grace58 · 06/04/2021 17:32

This is really interesting, mine came half a week early (very unusual for me) and was much lighter. I kept waiting for it to properly get going and it didn’t. I had the Pfizer one too!

turtlewurtle · 06/04/2021 17:35

I had Pfizer and periods were a week late.

Spinningaround21 · 06/04/2021 17:40

This is so interesting. I had first shot of Pfizer in February my period was fine as far as I remember. But my late March period hasn’t arrived yet. I had pms type symptoms bloating etc but nothing then it all faded away. I’ve taken reliable pregnancy tests and I’m not. No symptoms of that either and use condoms. I had my second last week.
I’m 42 I’m not worried about fertility but I can see why others may be concerned.

Spinningaround21 · 06/04/2021 17:41

*The first Pfizer was January. February was my period and it was ok

lightand · 06/04/2021 17:49

There was a thread on here last month, I think about the az vaccine and period changes afterwards. I will go and see if I can find it.

millenialblush · 06/04/2021 17:56

There was a thread on here 2 weeks ago, exactly the same side effects. Please report it on yellow card, we have been told time and time again it cant impact fertility but it's obviously doing something to the reproductive system.

lightand · 06/04/2021 17:58

Not sure this was the thread, but it might have been

AlphabetDinosaur · 06/04/2021 18:03

Mine was 3 days late after second dose of Pfizer.

Newchances · 06/04/2021 18:03

I didn't even realise but mine have been different too. More cramping with less blood? I really hope this doesn't have an effect on fertility after being told it wouldn't

Spinningaround21 · 08/04/2021 11:00

I probably should add to this I’ve come on today well over 2 weeks late. I went from end of feb to now and my cycles are so regular normally give or take a day or two. In my whole adult life I’ve hardly had many missed periods or really late ones.

I had my second dose of Pfizer last week so let’s see if it happens again.

9belle9 · 10/04/2021 09:55

Just posted this on the AstraZeneca thread for this... interesting lots have experienced this.

I had the vaccine on 18/3/21, my period is now a week late and no sign that it's on its way! 2 negative clear blue tests too so not pregnant. I feel like in a few months time when more of the 20-50yo population has been vaccinated more and more people will be talking about this as a side effect! It's been very draining not knowing why I'm so late, this has to be it, it can't be a coincidence surely?

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