The myth of the 28 day cycle

// 13 October 2011


A guest blog post by Saranga about the myths of the 28 day menstrual cycle.

Recently The F Word published a blog post about PMS . It’s a good article, well worth reading, but one particular statement prompted me to think about menstrual cycles:

“The majority of women of childbearing age have menstrual cycles of approximately 28 days”

This notion of a 28 day cycle is something I have had a lot of difficulty with recently. Women who use hormonal based contraceptives may well have a 28 day cycle, but those who aren’t can find their cycles varying between 20 days and 35 days (or more or less), for one period, or 12, or 24, or 36, or their whole lives. This variation in cycle doesn’t mean you are pregnant, or have an illness, sometimes it’s just how it works.

I mention this because recently I was over a week late and finally came on at day 35. Between days 28 and 35 I was terrified I was pregnant and ended up going to the local walk in clinic for a pregnancy test. When the result showed as negative I promptly burst into tears from the stress of it all. The nurse informed me that the worry about being pregnant could have caused me to be late (and looked utterly perplexed as to why I was crying, but she was nice about it, so that’s ok).

Now, I knew that stress can cause delay to periods, but I wasn’t aware that worry about the period itself could cause you to be late. I had assumed that stress in this case meant stress caused by the death of someone, or the loss of your job, not something as minor* as worrying about being pregnant.

I also wasn’t aware that cycles could vary so much. I thought if they did vary like this it meant you had polycystic ovaries, or a hormonal problem, or were infertile, or were miscarrying every month**, or something. None of that applied to me, I am healthy and well, so why hadn’t my period arrived? Ok, I have never been what you’d call bang on regular, but I had always thought I was only ever a day or two out. I only discovered I was so late this year because I have been keeping a menstrual diary, trying to work out when my cycle is. I’m 31, I started my periods when I was 14. You’d have thought I’d have settled down by now right?

Apparently not. Apparently, according to responses to a hastily contrived question on my blog and on twitter, many women have wildly irregular cycles, and it doesn’t mean there’s anything wrong with you. It’s normal.

My question to you all is: Why the hell don’t we get told this in school? Why isn’t it included in sex ed? Why is our national cultural notion of menstrual cycles that of a 28 day one? When you look on the NHS Direct website (or whatever it has morphed into these days) it doesn’t make it explicit that a varying menstrual cycle is actually fairly normal.

I couldn’t ask my friends about their cycles – most of them are on hormonal contraceptives, so I asked the internet. I felt so relieved when I received the answers. And now I want to broadcast this to everyone with a womb! You’re ok! You’re not weird! And a late period doesn’t always mean that you are pregnant, so don’t panic.

So please folk, can we stop talking about 28 day cycles as if they are the norm. As if wombs and uteruses and all our other bits comply to the same set of rules and (pun intended) cycles. At the very least I’d like to ask people to distinguish between those on hormonal based contraceptives and those who are not. It’d be doing us all a favour.

*minor.. hah….fear of pregnancy isn’t a minor thing, but it’s often treated as such, hence my use of this specific descriptor.

**to anyone who has experienced a miscarriage, this probably seems like a really flippant comment, and for that I apologise. However I mention it as a possible cause of late ‘periods’ because I know next to nothing about miscarriage, which is another subject that is woefully lacking in our sex education. I mean, shouldn’t we get taught about this stuff?

Saranga is a A 31 year old bisexual feminist reading many many comics. She runs New readers…start here! reviewing comics for people new to comics and also Pai where she talks about comics, feminism, BSL, comics, feminism and yet more comics. Her favourite hero is Supergirl. Also on twitter as @sarangacomics.

Image courtesy of Wikipedia used under the Creative Commons License.

Comments From You

Catherine Redfern // Posted 13 October 2011 at 9:22 pm

Good point always worth reiterating!

One thing though, if I remember rightly from the highly recommended book ‘Taking Charge of Your Fertility’, I don’t think that worrying can make your period late. However stress/worry CAN delay ovulation, which obviously in turn would delay your period. The time between ovulation and menstruation does not change but the time between your last period and ovulation can change. So possibly it was something you were stressed about earlier around ovulation time that delayed it, not worrying about being pregnant close to your due date as it wouldn’t be possible for that to delay it.

I’m sure someone more educated will correct me if I’m wrong! I do recommend that book though – it’s absolutely fascinating and not only for people trying to conceive as the title would suggest. Every menstruating person should read it.

gherkinette // Posted 13 October 2011 at 9:24 pm

Thing is, 95% of the women I know or have known do have a 28 day cycle. Most of them could set a watch by their cycle and are genuinely aghast to hear that I have a cycle that turns up when it feel like it (anywhere between 14 days and 6 months is normal for me).

Actually I used to be able to set my watch by friends and flatmates’ cycles. I’ve always been kind of envious. Imagine not having to alway carry sanitary protection just in case…

Frau BH (1848) // Posted 13 October 2011 at 9:28 pm

The problem is that all they concentrate on when you are at school is what will happen to you in the near future. You will get periods, this is why and here is the one reason that you won’t get a period. They don’t take into account that you will grow and change and that not everyone is the same. Until a couple of years ago, my periods were regular, but certainly not on a 28 day cycle.

I went into an early menopause a year and a half ago. Menopause in general was never explained fully when I was at school, let alone the fact that you can have an early one. And of course now, I have wildly irregular periods, so the 28 day cycle is a complete myth in my world.

Of course none of this is surprising, as knowledge is power after all – and the last thing they want is for women to have power over their own bodies!

Beth // Posted 13 October 2011 at 10:06 pm

The nurse was WRONG. Worry about your period CANNOT cause you to be a few days late.

The time from when you ovulate to when your period starts is roughly the same every month – in most people between 10 and 16 days (very rare to be outside this time and often indicative of a problem, at least if you’re trying to get pregnant). So if you were five days late that means you ovulated five days later than usual. So stress around that time would have made a difference, but stress a couple of days before your period is due utterly cannot.

If you’ve not read Taking Charge of Your Fertility, READ IT! :) It’s an amazing book; even if you don’t want to use it for pregnancy achievement or avoidance you will learn SO MUCH about your body. Especially that vaginal discharge is normal, and can be a sign of fertility; even if it’s in quite copious amounts. And that – as you say – the mythical 28 day cycle is rare, and the myth can cause stress for both pregnancy avoiders and achievers – AND that it can cause people to either get pregnant when they think they can’t, or not get pregnant when they want to because they stop having sex before their fertile period starts.

That miscarriage comment does seem rather flippant but I do see what you’re saying. If you have any questions about miscarriage please ask me. It’s only happened to me once but it’s left me quite an expert :/

Milly // Posted 13 October 2011 at 10:55 pm

If you’re interested in tracking your cycle, and if you’re a bit of a geek, I can heartily recommend

Once you’ve put in data for a few months it starts doing pretty graphs – and I’ve learnt the fun fact that I have an average cycle duration of 27 days, with a standard deviation of 1.7 days. Cool huh!

It’s a pretty well used website so it would actually be fascinating to see the combined data from everyone on it – would reveal whether or not 28 days is actually the average, and it would give a good sense of the variety of cycles in a given population.

TFK // Posted 14 October 2011 at 7:50 am

I have had a 40 to 42 day cycle my entire life. When I was 5 days “overdue” with my first child I was repeatedly bullied into having an induction for nearly 2 weeks, fortunately I had a midwife who understood what the docs were unable to. I gave birth 17 days “late” 1 day before I had worked it out. I know my body.

Rachel K // Posted 14 October 2011 at 8:32 am

Saranga – great post. I totally agree with you that I wish we’d been given this information in school! I don’t think I’ve ever had a regular monthly period except when I was on the combined pill (and even then it was a perfectly regular 29 days :-S). Since I came off it a few years ago and started cycling through other contraceptive methods, trying to find one that suits me, I’ve been all over the place, and not having a so-called normal baseline has made it hard to tell what part of that is just me and what is the contraceptives not agreeing with me.

I actually don’t think the miscarriage comment is far off base. I can think of a couple of times, a few years ago, when I was convinced an irregular/heavy period was down to that and found it very stressful. With the benefit of hindsight, I now don’t think that was the case. I wish I’d had a better idea of these things at the time!

Milly – thank you for the link to MonlyInfo! It looks great and I’m looking forward to trying it out.

JessLeeds // Posted 14 October 2011 at 9:33 am

Why don’t they tell you ANYTHING that happens to you in your twenties at school? I’m 26 and me and my girlfriends spend a good 60% of our time comparing notes about what is happening to us. The hair thing? What the chuff is with the hair thing! And when your 22, you boobs will grow by three cup sizes IN A DAY. Oh, and buy more loo roll for That Time, because the poo thing, apparently (and it took three bottles of wine for this to be admitted) happens to everyone! And you NEVER get told about the poo thing at school!

My cycle couldn’t be more irregular if it tried and I’m not taking anything for it. Ryan Air is more punctual than my period.

Susan // Posted 14 October 2011 at 4:43 pm

My cycle ranged around 24 to 29 days for more than 20 years, then it got more and more irregular until menopause. The long gaps were welcome, the 2-week cycles weren’t! I didn’t know someone’s cycle could be that irregular (without a medical cause) all their life. OMG how inconvenient!

HarpyMarx // Posted 14 October 2011 at 8:57 pm

Interesting article has made me think. I recall being told re sex education, periods and from my mother it was a 28 day cycle. My periods started when I was 11 and I was always bang on 28 days, very rarely late or early. But since the last 6 months my periods have been unpredictable, sometimes 21 days, sometimes 28 and sometimes 35. I have always had heavy periods (and that’s another thing they don’t teach you about…!) and I never really thought about this as my mother and sister always had heavy periods. Reading your post made me think as I have always been 28 days but now things have gone weird….and am in my early 40s. The doctor has made me an appointment to go for a scan, which has freaked me a bit but nevertheless it should help, I hope (also it could also be connected to my dodgy thyroid gland….). But again thanks for writing this and it makes sense that it isn’t all about 28 day cycles, that we are different.

Laura // Posted 14 October 2011 at 10:52 pm

OMG the (whispers) poo thing. I hear ya. I am not yet 26 – the hair thing…is this another womanly delight I have to look forward to?

Laurel // Posted 14 October 2011 at 11:44 pm

i always found the myth of it being a tablespoon the weirdest. per period? per day? per hour? per squirt? (mmm…) what?

sohcahtoa // Posted 15 October 2011 at 12:14 pm

Can I also point out that even women on hormonal contraception do not always have regular cycles? Not only can some kinds (especially the mini pill and the injection) stop periods or make them very irregular, but even the combined pill, which is meant to give you a four-week cycle if taken normally, can mess things up – or at least it has in my case several times! And, on the subject of not being told things, there is nothing in the information leaflets (or NHS/FPA advice) that warns about this, apart from a few mentions of spotting (which isn’t the same thing!). When I found myself bleeding at the wrong time and, concerned that this meant that the pill wasn’t working properly, went to the doctor, I received some bemused and sometimes patronising responses: ‘Of course, that’s normal… why are you here?’ Well, if that’s normal (or, at least, not abnormal), why is that information not available anywhere? Eventually a family planning nurse suggested that I see irregular bleeding as a side-effect of the pill, which made sense (though it also opens up another can of worms).

Rachel // Posted 16 October 2011 at 8:28 am

Oh crikey, yes – the poo thing! I thought it was just me!

What’s the hair thing?

Saranga // Posted 16 October 2011 at 10:15 pm

Hi all.

Thank you for the comments! I thought this post might be ignored as uninteresting so it’s heartening to have discussion from you all. I thank you all for the extra bits of info and links. Some of it I wasn’t aware of, but I am really glad I’m not the only one who’s still ignorant! Thanks for the clarifications guys :)

The poo thing.. oh yes, how can I be discreet here.. bowel movements become a little easier around the times I’m due on! That, cramps and pms are my clues as to when I know I’ll come on. I’ve come to realise I need to listen more to my body than the calendar.

The hair thing, well I’ve just got more sprouting chin hairs as I’ve got older. I’m so obsessive about plucking I have no idea whether they correspond to my cycle or not. Damn things.

sianandcrookedrib // Posted 17 October 2011 at 4:02 pm

Agree with so much of this post!

My cycle is quite hit and miss even on the pill, and off the pill there were plenty of ‘ohshitohshitohshit’ months. Even last year, on the pill, my period was really late and i was freaking out.

But the worst thing that no-one told me about was how after you take the morning after pill your period kicks in and is really really heavy. i thought i was sick or that i was miscarrying (i know that makes no sense but i was scared and relatively young) until i got my friend to come over and reassure me. They need to tell you what is going to happen because it’s scary when you don’t know what to expect and your body starts going haywire.

And yep, your boobs growing after you’ve ‘stopped growing because you’re in your 20s’ meant i was wearing the wrong bra size for years and years.

Women’s health is so silenced, ignored! I didn’t even know about mooncups until i read this site in 2007. Why don’t they teach you about mooncups and sea sponges instead of selling you to tampax and kotex from day one. I learnt so much more about my body from talking to friends about their experiences and sites like this.

PS. what’s the poo thing?

JessLeeds // Posted 18 October 2011 at 4:11 pm

y’know, when you, poo, a fair bit…

(I was convinced for years it was just me too!)

gherkinette // Posted 18 October 2011 at 10:45 pm

Doctors don’t know about the poo thing. Well, the male ones anyway.

I get it really really badly. My period flares my bowel disease something shocking and even when sitting in A&E getting put on a drip for dehydration after fainting a few years ago everyone was still carrying on like it was unheard of. (Admittedly most people do not start the poo thing five days before, the five days of and the five days after). I happened to run a pill pack together, realised it stopped it and went on Depo to stop the whole cycle before it killed me off.

It wasn’t until I started reading feminist sites I realised i wasn’t so kind of unique pooing freak…

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