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  • Ruby Forbes

The ins and outs of irregular periods

Updated: Jul 26, 2022

Panty liner with petals

For many of you, periods have been an annoying but dependable occurrence in life. Once a month, you hunker down with chocolate and blankets, ugly-cry at your favourite Hugh Grant film, and ride out the crimson wave. But now, suddenly, things have become different. Maybe your period has become heavier, and more frequent, or even lighter. Maybe you’re seeing a lot more spotting. What, exactly, is going on?

The culprit behind all of this is perimenopause. Yep, alongside hot flushes and inexplicable rage, irregular periods are just another string to mother nature’s capricious bow. This might all seem bewildering and confusing, but this is a very natural phase of life. Your body is simply preparing itself for menopause. In other words, it’s getting ready for the next stage of your life!

Typical symptoms of irregular periods

Irregular periods can mean a whole host of things. Here are some typical symptoms that you might find familiar:

  • Heavier periods

  • More frequent periods

  • Less frequent periods

  • Spotting

  • Brown or dark blood

  • Missed periods

When your body hits perimenopause, there is a lot of hormonal fluctuation going on. As you may know, this can take a few years to settle down, which might feel frustrating.

However, at Olivia we firmly believe that knowledge is power. Knowing what’s going on with your body is half the battle, and can go a long way in easing any stress associated with these changes.

So, let’s dig deeper.

The menstrual cycle

How about a quick refresher on how a typical, pre-perimenopause, menstrual cycle should look?

Your menstrual cycle begins on the first day of your period, after which your uterus lining starts to build up again. During this stage, you will probably notice more energy, due to rising oestrogen levels. This stage culminates in ovulation (the release of a mature egg from your ovaries), and another oestrogen boost leaves you feeling confident, fearless and sexy.

In the second phase of your cycle, progesterone rules the roost. In this stage, your body is essentially preparing for a possible pregnancy. Chances are, you will be feeling less sociable, with a Godzilla-like appetite. That is progesterone, keeping you safe and well-fed in case a baby comes along.

During this stage, the mature egg travels to the uterus. If it is not fertilised, oestrogen and progesterone levels drop rapidly (leading to impromptu sobbing marathons over misplaced keys) which sends a signal to your uterus to break down again. Leading to the first day of your period, and a brand new cycle.

The perimenopausal cycle

Perimenopause puts a spanner in the menstrual cycle works. Fluctuating hormonal levels alter your typical cycle, leaving you with those wacky, what-the-heck-is-happening symptoms.

Perimenopause is essentially the occasionally nerve-wracking rollercoaster ride that gets you to menopause (which technically lasts one day and marks the twelve-month anniversary of your last period). The perimenopausal body becomes less receptive to oestrogen and FSH (the hormone that stimulates your follicles to grow eggs in your ovaries). This means you start ovulating less frequently. The result of this is less progesterone in the body, and can feel like missed periods. Less progesterone, as you’ll see below, can affect cycle length, and exacerbate PMS symptoms.

Remember that rollercoaster, with its ups and downs and gravity-defying loops? Maybe that’s a good analogy for how your irregular period symptoms feel. Let’s strap ourselves in and have a closer look at what’s actually going on.

menstrual cup tampons

Heavy periods

You might notice that your flow has gotten heavier recently. This could be due to higher levels of oestrogen, in relation to progesterone. Higher oestrogen levels can lead to the lining of the uterus building up more, resulting in a heavier bleed when it does eventually shed. A missed period can also lead to a heavier period.

Shorter cycles

Having a more frequent cycle is often associated with lower oestrogen levels, which is common in the earlier stages of perimenopause. Lower oestrogen levels mean less uterus lining to be shed. Bleeding is consequently lighter, and lasts a shorter amount of time. The inconvenience of shorter, unanticipated cycles is no joke! Might we suggest period pants and panty liners, to account for any unexpected incidents?

Longer cycles

A longer cycle is related to anovulatory cycles, in which you don’t ovulate, and this is associated with the later stages of perimenopause. Longer cycles are defined as lasting more than 38 days. Symptoms like hot flushes, night sweats and vaginal dryness are also associated with this later phase, due to low oestrogen.

Anovulatory cycles are more common than you might think, and can even occur during your fertile years. In this case, they are often related to stress, disordered eating and over-exercising.

However, they are also associated with perimenopause. This is due to the perimenopausal body becoming less receptive to oestrogen and FSH. With your body less able to pick up these hormones, ovulation becomes less frequent. Because ovulation produces progesterone, your body then has less of this particular hormone circulating in its system. And what is the effect of less progesterone? Altered cycle length, premenstrual spotting, increased PMS, sleep issues, tender breasts and headaches.

Perimenopause is often associated with spotting and bleeding, rather than menstruation. However, it’s important to know that you can still get pregnant during this time, as it’s not always easy to tell whether bleeding is from an ovulatory or anovulatory cycle.


Premenstrual spotting indicates that progesterone is low, which is common during perimenopause. Spotting is usually the result of fluctuating hormones, and the build-up of your uterus lining. As noted above, period pants and panty liners can be a lifesaver for any unplannable moments.

Brown or dark blood

This is normally old blood exiting the body, and it can have a varying texture and odour depending on how long it’s been there. If it smells bad, this could be a sign of infection.

Absent periods

Maybe you can’t even remember the last time you had your period! And then, suddenly, it rocks up as a most unwelcome guest, just when you thought the party was drawing to a close.

Fluctuating hormones are again to blame for absent or missed periods. As you ovulate less frequently, your uterus doesn’t shed its lining as often, leading to what feels like a missed period. After twelve missed cycles, you’ve officially made it to menopause.

When to see a doctor

All of the above are normal symptoms and are merely an indication that your body is winding down on the fertility front, in order to enter the next phase of life. However, in some cases, there are symptoms that might need to be looked into further:

  • Bleeding is extremely heavy (e.g. you go through one or more pads or tampons in an hour)

  • Your period comes more than every three weeks

  • Your period lasts for more than 7 days

  • You bleed after twelve months of missed periods (this should always be investigated, as it might indicate uterine cancer)

Irregular periods can be a real annoyance, especially if they have just appeared out of nowhere. But hopefully, this article has helped to demystify the perimenopausal menstrual cycle. Knowing what’s going on can go some way in easing the frustration and stress associated with irregular periods, leaving you calmer and more able to tackle the day.


“Anovulatory Cycle: Symptoms and Treatment.” n.d. Healthline. Accessed February 9, 2022.

Ernst, Holly. 2018. “Perimenopause periods: Key symptoms and management.” Medical News Today.

Hill, Maisie. 2021. Perimenopause Power: Navigating Your Hormones on the Journey to Menopause. N.p.: Bloomsbury USA.

“Menopause - Symptoms.” n.d. NHS. Accessed February 9, 2022.

Nwadike, Valinda R. 2018. “Follicular Phase: What It Means If It's Short or Long and More.” Healthline.

“Perimenopause - Symptoms and causes.” 2021. Mayo Clinic.


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