Study finds “Association Between Menstrual Cycle Length and COVID-19 Vaccination”

[letmeeatcrisps]

Some news outlets today have briefly covered this…cycle length prolonged by 19 hours on average post vaccination. Is anyone else somewhat alarmed by it or are the results not statistically significant enough to worry about? Does this happen with other vaccines?
TIA mumsnet science heads x
journals.lww.com/green-journal/Fulltext/9900/Association_Between_Menstrual_Cycle_Length_and.357.aspx

journals.lww.com/greenjournal/Fulltext/9900/Association_Between_Menstrual_Cycle_Length_and.357.aspx

Sorry the initial link is broke

Did you actually read the study? This is the conclusion:

"Our findings are reassuring; we find no population-level clinically meaningful change in menstrual cycle length associated with COVID19 vaccination. Our findings support and help explain the self-reports of changes in cycle length. Individuals receiving two COVID-19 vaccine doses in a single cycle do appear to experience a longer but temporary cycle length change. Coronavirus disease 2019 (COVID-19) vaccination is not associated with changes in menses length."

Cue the minimising posts.

•nothing to see here’

‘It’s mild’

Etc etc

Yes I find it alarming and not at all surprising given the changes I and other friends/relatives experienced after the vaccine. I wish there was more transparency about side effects.

We’ve not had a mass vaccination rollout like this in what, 60 years? More? It’s only in the past 20 years or so that women talk so freely about menstruation, and certainly only in the past 20 years that we’ve been able to talk to so many other women and compare notes as it were. Plus, let’s not forget that it’s still difficult even now for female-only issues to be taken seriously.

So… back when the last mass vaccination took place in females aged 18+ (because many woman’s periods aren’t clockwork for the first few years) there just wouldn’t have been the communication for it to be noticed.

I don’t understand why that is important @SnakeRabbitMouse

Sorry I meant @RachC2021

Very worrying. The jabs are safe until they aren't. First myocarditis and now this (concerns many women raised months ago but were dismissed). I wonder what will be the next side effect to appear?

@hamstersarse

Cue the minimising posts.

•nothing to see here’

‘It’s mild’

Etc etc

It's only women being hysterical, so who cares .

@hamstersarse

Sorry I meant *@RachC2021*

It’s because the menstruation side effects might actually be common to many other vaccines too. But because the vast majority of vaccines are given to babies/children now there is simply no way to know.

The side effects of myocarditis from Covid-19 vaccines only became apparent when millions of people were getting jabbed at once. The same thing could be true of menstruation side effects too (if ever proven).

I think the title I’d this thread might be a bit misleading given the results of the study.

I always thought temporary menstrual changes were common with vaccinations and viral infections as part of the bodies normal immune response? As in, the body is preparing itself to fight off infection and recognises it’s not an ideal time to conceive. I’m sure I read that years ago as a biology student- don’t know if it’s accurate but that’s what I always assumed.

@hamstersarse

Cue the minimising posts.

•nothing to see here’

‘It’s mild’

Etc etc

Exactly. @hamstersarse My periods have been all over the place since receiving the jabs. When ttc after miscarriage it's upsetting given how regular I was previously. Wondering if it caused ED would it be so brushed over.

@LadyWentworth

I always thought temporary menstrual changes were common with vaccinations and viral infections as part of the bodies normal immune response? As in, the body is preparing itself to fight off infection and recognises it’s not an ideal time to conceive. I’m sure I read that years ago as a biology student- don’t know if it’s accurate but that’s what I always assumed.

Yes - stress, colds, flus, viruses, physical strain all delay periods. It's not surprising that two doses in a month (why?!) would cause changes too. This just seems like one of the vaccine-doing-its-job side effects?

I have just read this study. It basically says in the month after vaccine your cycle can be a day longer, then it returns to normal

I don't think its a cause for concern

@hamstersarse

Cue the minimising posts.

•nothing to see here’

‘It’s mild’

Etc etc

Well ... did you read it? I'm not minimising anything. I'm simply saying what the authors of the study concluded - which is the opposite of what OP is attempting to suggest. Sorry if it bothers you.

I wouldnt know if my period was 19 hrs late - I go for "expected some point these 4 days". Are some people so predictable that they know their period is going to start at 10am on Tuesday?

It’s funny the study says a day late but anecdata is much more disruptive experiences

Well we already knew this due to the tens of thousands of yellow card reports. What I'd like to know is WHY? What exactly is causing these menstrual issues? How does a vaccine that targets the immune system cause women to shed their womb lining? And its not just extended menstruation, there have been many reports of post menopausal women bleeding for the first time in years post vaccination. Perhaps if they could explain the reasons for this it would allay some fears.

I'd worry about the number of people excluded - it's over 60%. That's not indicative of dodgy dealing, or anything, more that it's hard to get good data, but it's still not great when you've excluded more than half of your original sample.

I didn't really see any discussion of the skewness of the data, though I admit I did skim read a bit. It's much more concerning, I would say, if a few people have long delays, than if a lot of people have short ones (as the latter scenario fits better with the "stress" hypothesis).

Will try and look properly (not on a phone) later, when I should be able to see the graphs better, and see whether there's anything that shows the skewness.

Doesn't look very skewed, but the graph's hard to read. They also don't seem to have discussed the spread of the data. If some people were having shorter cycles after vaccination, and some longer, then an effect might be hidden if you just look at the means.

I'm not saying that's what's going on - but I'm surprised they don't seem to have considered it. There's a brief comment about the overall distribution being the same, but nothing to say how they determined that (I would have compared the sample variances, myself, even if only to reassure myself I wasn't missing something important.)

The reasoning is explained in that study. It's immune response. Other vaccines also cause similar, not just Covid.

"mRNA vaccines create a robust immune response or stressor, which could temporarily affect the hypothalamic-pituitary-ovarian axis if timed correctly.18–20 Our findings for individuals who received two doses in a single cycle supports this hypothesis. Given the dosing schedule of the mRNA COVID-19 vaccines in the United States (21 days for Pfizer and 28 days for Moderna), an individual receiving two doses in a single cycle would have received the first dose in the early follicular phase. Cycle length variability results from events leading to the recruitment and maturation of the dominant follicle during the follicular phase, processes known to be affected by stress.12,21 In contrast, an acute severe illness with or without septicemia, such as COVID-19, could be catastrophic to hypothalamic-pituitary-ovarian axis function, sometimes permanently.18,22"

@110APiccadilly

I'd worry about the number of people excluded - it's over 60%. That's not indicative of dodgy dealing, or anything, more that it's hard to get good data, but it's still not great when you've excluded more than half of your original sample.

I didn't really see any discussion of the skewness of the data, though I admit I did skim read a bit. It's much more concerning, I would say, if a few people have long delays, than if a lot of people have short ones (as the latter scenario fits better with the "stress" hypothesis).

Will try and look properly (not on a phone) later, when I should be able to see the graphs better, and see whether there's anything that shows the skewness.

It depends

Do they say anything regarding the mechanism of missing data? If not MCAR then can introduce bias, but then they should use multiple imputation to estimate.

@HappyGreen

Well we already knew this due to the tens of thousands of yellow card reports. What I'd like to know is WHY? What exactly is causing these menstrual issues? How does a vaccine that targets the immune system cause women to shed their womb lining? And its not just extended menstruation, there have been many reports of post menopausal women bleeding for the first time in years post vaccination. Perhaps if they could explain the reasons for this it would allay some fears.

Anything that causes an immune response can also lead to menstrual cycle changes

Be that infection or vaccination

I linked this on another thread which I think is helpful. I think important to consider the opinions of experts who summarise all of the current evidence.

Here's a good summary of the current research by an immunologist at imperial who specialises in reproductive health.

twitter.com/VikiLovesFACS/status/1479359757450457088

She also has a good explainer on vaccines and fertility:

twitter.com/VikiLovesFACS/status/1367099701238116353

In fact, multiple strands of evidence tell us that COVID vaccines do not reduce fertility.