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What is a Period – and Why Menstruation is Amazing

How often do you celebrate the fact that you have periods? It’s fair to say that most of us aren’t breaking out the prosecco when the familiar rumblings of PMT cramps start up each month. Well, not unless it’s for medicinal purposes, of course.

Instead, we are braced for our symptoms, worrying about having a pad, tampon or some period underwear to hand and generally bemoaning our red curse. That’s not to mention navigating the shame and embarrassment that society has shackled to the very notion of bleeding every month.

We’re not here to tell you that menstruation is a skip through a flowery field in the sunshine, but let’s take a moment to reframe this whole experience.

A body’s journey through the menstrual cycle is, in fact, extraordinary. We learn so much about our health, hormones, and strength through its ebbs and flows.

So today, we’re going to talk about the menstrual cycle and how periods work before discussing the many empowering positives of this unique bodily experience.

Here’s what we’ll be deep diving into:

  • What a period is and how the body menstruates

  • The phases of the menstrual cycle and how they impact the body

  • What your period can tell you about your general health

  • Why menstruation is critical to the survival of the human race

To begin, let’s get right back to basics. You can be forgiven for being the proud owner of a menstrual cycle yet not having the full scientific facts about how it works at your fingertips.

Here’s a refresher.

What is a period?

A period (menstruation) is the part of your menstrual cycle in which you bleed. It occurs roughly every 28 days and forms one phase of the four that comprise the entire cycle.

The blood and tissue that leaves your body via the cervix and vaginal opening is the uterine lining shed from the uterus.

Bleeding usually happens when the hormones signal to your body that pregnancy is not in progress; therefore, the uterus no longer needs the endometrium (uterus lining) in place.

Hormones called prostaglandins move into the uterus and cause contractions, which trigger the shedding of the endometrium. They sometimes end up in the gastrointestinal tract (GI) too, which is why some people have increased bowel movements during their periods.


Fascinating Fact

Periods can last between three to eight days, and the average span of bleeding is five days. This occurs around days 21 – 40 in the menstrual cycle.

The Menstrual Cycle Explained

Let’s look at the menstrual cycle’s three other phases.

The Follicular Phase

Following your period, the body goes into the follicular phase of the menstrual cycle. At this stage, it is biologically preparing for potential pregnancy and getting all its ducks in a row.

Now is the time when the body gets ready for its egg. Our trusty friend oestrogen sends a message to the uterus that it’s time to thicken up and prepare for an egg to arrive.

During this phase, the follicle-stimulating hormone gets to work and stimulates the ovarian follicles to produce eggs. At this point, your oestrogen levels will rise and peak, and if all goes to plan, an egg will be ready for fertilisation.


Fascinating Fact

Every ovarian follicle contains an egg, but only one egg will generally be ready for fertilisation each month.



Now it’s time for the phase that launched a thousand tracker apps – ovulation. The luteinising hormone (LH) kicks in as your oestrogen levels rise.

The LH has a job to do, and that’s to make a follicle rupture and release an egg. Generally, this happens around day 14, but we are all different, hence sky-high tracker app sales.

At the point of ovulation (which can happen anywhere from day 11 – 16), a mature egg will start its journey from the ovary and through the fallopian tube to destination uterus.

Once it arrives, the egg is on an approximate 24-hour countdown for fertilisation before it begins to degrade.


Fascinating Fact

A mature egg takes around 3 to 4 days to travel from the ovaries to the uterus.


The luteal phase

Back in the ovaries, the empty follicle has turned into what’s known as corpus luteum, and the cells produce oestrogen and a large amount of progesterone.

The hormone progesterone starts telling the uterus it’s time to get serious about thickening up the walls – a fertilised egg could be incoming.

If you have conceived, the fertilised egg will move into your uterus and attach itself to the lining. It’s now that the hormone-producing placenta will form to support the foetus.

However, if the egg isn’t fertilised, oestrogen and progesterone levels drop, leaving the door wide open for the prostaglandins to start their work.

They’ll cause the uterus to contract, the lining to shed, and the bleeding begins again.


Fascinating Fact

Menstrual blood tends to be bright red during the beginning of your period as it is new and hasn’t had time to react with air. Blood that comes in the later days of menstruation tends to be darker due to air reaction.

Menstrual blood – how much do you lose?

As ever, it depends on the individual, but most periods involve blood loss of around 30 – 75ml. If you prefer to deal in different measurements, that’s 5 – 12 tsp.

For many of us, that might seem like a lot less than it feels every month, particularly when clots are involved.

When medical professionals talk about heavy periods, they generally mean blood loss of around 74 – 88ml, which is 5-6 tbsps.

If you suspect you are bleeding more than this each month and your period is so heavy that it interferes with your daily activities, speak to your GP immediately.

Seeking medical advice is vital because prolonged bleeding can lead to anaemia.


Fascinating Fact

The average age for menstruation is 12, which is five years earlier than in the 1800s. Scientists believe this is down to improved nutrition and, therefore, more fat cells. Oestrogen is produced in fat cells, and the level of it in our bodies can trigger the start of the menstrual cycle.

My menstrual cycle isn’t regular – is there something wrong with me?

Please don’t panic because it’s perfectly normal to have variability in your monthly cycle.

There are a few reasons for that – and one of them is that you may not ovulate every month.

A lack of ovulation can happen during adolescence and also during perimenopause when you might find you miss a period, or it’s delayed and ends up being very heavy.

There is also a myriad of other reasons for cycle fluctuations – conditions like PCOS, fibroids and uterine polyps can all contribute to this.

As ever, the best thing to do if you are worried is to consult your GP to investigate. You certainly don’t need to suffer in silence when there are treatments to help you with any discomfort and alleviate your worries.

Your menstrual cycle is amazing – here’s why!

It can be messy, painful, and disruptive, but it’s time to celebrate your incredible menstrual cycle.

Period shame is one of the most egregious crimes of the patriarchy because it’s turned this natural phenomenon into something to hide and feel shame about.

But without menstruation, the human reproductive cycle doesn’t work – and therefore, human life doesn’t continue.

In the womb, a foetus literally depends on the endometrium for survival. The blood and tissue are life-giving for those nine months and vital to the continuum of the species.

It’s also a natural monthly pregnancy test for most of us. Every 28 days, our period will let us know if we’re expecting a baby or not – no trips to Boots required!

Of course, some women still experience bleeding and spotting when pregnant, but heavy bleeding usually indicates something is wrong.


Fascinating Fact

25 – 30% of women will have light bleeding or spotting during pregnancy, commonly in the first trimester. This can be down to changes in the cervix, implantation bleeding or vaginal infection. If you are worried about bleeding, seek medical advice immediately.


Health data incoming

Did you know that having a period each month is a sign of good health?

Regular menstruation is an indicator that everything is working well in the sexual health organs department. It also lets you know your hormones and thyroid are operating as intended.

If your period doesn’t arrive, you’ll know something is happening – whether that’s pregnancy, problems with body function or an issue to investigate.

Being over or underweight can contribute to changes in your menstrual cycle, as can high-stress levels.

For many of us, the absence of a period could be the first sign that our body needs something to change or be fixed fast.

Keep an eye on your cycle to be immediately aware if something changes dramatically and your body needs you to act.


Fascinating Fact

During the average woman’s lifetime, she will have around 480 periods – usually between the ages of 12 – 52.

Periods make you live longer

Finally, and you will love this one, periods are believed to be key to women living longer than men.

That’s right, American longevity researcher Thomas Perls argues that bleeding each month gives women a life-expectancy advantage.

The theory goes that free radicals, which increase your chances of developing age-related diseases, need iron to produce.

Every month when we bleed, the iron levels in our body are depleted and therefore, so is the production of free radicals.

So, according to Perls, women naturally age slower due to their menstrual cycle.

If that’s not a cause to pop that prosecco, we don’t know what is!

Evidence Based
This article has been reviewed by our Kari Health Experts and Editorial Board to ensure accuracy and reliability of the information presented. However, please note that the content provided is for informational purposes only and should not replace advice from your medical professional.

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