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Health & Body

How can I tell if my cycle is regular or irregular?

How to understand what makes your cycle ‘regular’ or ‘irregular’ (oh and, there’s no such thing as ‘normal’).

5 min read | October 19, 2021
All this talk of ‘time of the month’ has reinforced the idea of the ‘regular’ cycle, but we want to make it clear that that’s not always the case.

Hands up if you’ve ever wondered whether your cycle was ‘normal’? PSA: there’s no such thing as normal because our bodies are all different. But, just like our evidence-backed menstrual products at Hummingway, we make sure everything we talk about is rooted in science. While ‘normal’ isn’t a term we deal in, you will see us talking about what is more ‘typical’. No shoulds, no shouldn’ts, just plain old (because some of it, shockingly, is pretty dusty) research that backs up what is ‘regular’ or ‘irregular’. 

This doesn’t mean striving to achieve a ‘regular’ cycle. Certain lifestyle factors can impact your cycle but before we get to that, it’s important for you to get clear on what exactly is a regular and irregular cycle. Tracking your cycle is the second best thing you can do to better understand your cycle and how to navigate it. The first best thing is to have all the information that’s out there (and we’re working on getting you even more). So, let's get into regular vs irregular menstrual cycles and what they typically mean.

An irregular cycle and a regular cycle aren't necessarily the good and the bad. Having menstrual irregularity with your cycle can simply be caused by a few factors, from changing hormone levels to hormonal birth control. With that in mind, we’ve got a few myths to debunk, so let us give you the whole picture on regular vs irregular menstrual cycles: 

 #1: Your cycle happens every month vs Your cycle doesn’t always happen every month

You could have between 9-15 cycles per year. That means they don’t necessarily come back each month like clockwork. And because the length of our cycles varies (see below), you may have more or fewer than twelve cycles a year. You don’t need to be a mathlete to work that one out. All this talk of ‘time of the month’ has reinforced the idea of the ‘regular’ cycle, but we want to make it clear that that’s not always the case.

You could have noticed a missed period or menstrual cycle irregularity that may not last the same length as a regular cycle. But this isn't always something to worry about, since hormonal fluctuations, pregnancy, or even stress can affect menstrual cycle irregularity. However, if you do notice abnormal bleeding, extremely painful period pain, or other abnormal symptoms, it's best to see your health care provider. 

#2: Your cycle always lasts a month vs No cycle lasts the same length of time

In adults, a normal cycle lasts between 24 and 38 days (you might occasionally have one shorter or longer and that’s okay) — it’s fine if your cycle varies in length between 7 and 9 days. So you could have one cycle that lasts 25 days one month, another that lasts 33 the next. 

And to all the younger people with periods – if you’ve been menstruating for two years or less, the window is a little wider: between 21 and 45 days (again, occasionally your cycle could be longer or shorter. Don’t sweat it.). 

#3: Your period only last 3-4 days vs The length of your period can vary

Not sure who spread this rumor (maybe school sex ed and health teachers in the 90s?) but periods don’t have to last between 3-4 days. Sure, that happens for many bodies. But actually menstruation can last up to 8 days before it’s considered irregular. And if you’re wondering about the amount of blood (we see you menstrual cup users), bodies can shed between 5-80 ml of fluid (that’s up to 16 teaspoons) over the course of your period. 

So when we say ‘irregular’, we’re not talking about cycles that don’t recur each month. It’s more nuanced than that. 

An irregular cycle could look like: 

  • One that often falls outside of the 24-38 days range (21-45 for people who have been menstruating for two years or less). 

  • Bleeding that lasts more than 8 days.

  • Uterine bleeding that’s heavy enough to fill one regular pad or tampon every hour for multiple hours (or over 80ml for a whole period, if you’re measuring with a cup).

  • Irregular bleeding outside of your period (that isn’t regular ovulation spotting).

  • Excess facial hair, body hair, or thinning hair on the head.

  • Pain (or any symptom) that gets in the way of daily life.

  • A different smelling, itching, burning, or sore sensation in the vulva.

  • Brownish or greenish discharge, or discharge that’s suddenly thicker or heavier consistency. 

Menstrual cycle characteristics can vary. A regular menstrual cycle will "typically" be different than an irregular menstrual cycle through a few characteristics from the length of the cycle to how much uterine bleeding you're experiencing outside of your regular period. But, irregular or regular periods can still change depending on the hormonal birth control you might be taking, changing hormone levels, stress, and more. 

Either way, it's important to understand that no menstrual cycle can necessarily be deemed as a regular menstrual cycle because everyone's body is different and everyone's cycle is going to differ. 

There are certain factors that can impact your cycle, like anxiety or stress which can have a physical impact on your period (like not bleeding one month, or having a delayed period). If you’ve noticed any of the above, we’d recommend speaking to your health care provider to get the right menstrual products for you. The most important thing to remember is that just like Cady Heron’s lightbulb moment on limits, the ‘norm’ does not exist. 

Cady Hero in Mean Girls realising 'the limit does not exist'
About Author

Your hormones can be complex and unpredictable. That’s why we’re here, on The Regular, to do what’s long overdue - to demystify what’s going on with our reproductive systems, our hormones and our whole cycle.

We’re here to support your day-to-day queries serving useful content that is uncomplicated and unbiased. No topic is too complicated or too specific for us to address/focus on.

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