Period 101

Everything you need to know about periods and your menstrual cycle

We, at The Body Shop are calling it as it is – Periods are Normal, Society is Strange. No more ‘that time of the month’, just call it a period. We’re ready to #DropThePWord into our conversations and end period shame. So, here we are starting those conversations, answering the questions to give people the understanding about their body that everyone deserves.


A period is what happens when the lining of the uterus (or womb, it’s the same thing) falls away. If you want to be really geeky, this lining is called the endometrium. We always typically think of a period as being just blood. But actually, it’s a lot more. It also contains mucus, which is why it can be a bit sticky or clumpy, as well as old cells, and actually a fair bit of water. This time of the month is also referred to as ‘menstruation’. The menstrual cycle is the term used to refer to the entire hormonal process that happens to cause your period to occur, and spans the entire time from the start of one period until the start of the next.

Period 101

Why do we have periods?

Well, quite honestly, it’s because you didn’t get pregnant. And this sounds a bit weird because most women are not even trying to get pregnant most of the time! But your hormones don’t really understand that. So, every month your body goes through a cycle of hormonal changes that result in the lining of the uterus thickening up so that it is ready to house a fertilised egg. Midway through the menstrual cycle your ovary should release an egg which is called ‘ovulation’ and if this does occur, the egg leaves behind its shell, which is called the ‘corpus luteum’. The corpus luteum can survive up to 14 days and if an egg is not fertilised it will start to degrade, and this causes a drop in menstrual cycle hormone levels. When these hormones drop, the thickened lining of the uterus is no longer supported so it begins to fall away, and this is your period.

Going through this whole process requires the cooperation of a lot of different hormones and chemical processes and requires a lot of energy and nutrients. That’s why there are numerous different reasons for why the cycle might not quite happen in the way it’s designed. Factors such as stress, malnutrition, illnesses (both long-standing or a short bout of illness) as well as hormonal diseases, can result in your period not arriving at the time that you’re expecting.

Contrary to popular belief your period is not a way of your body ‘detoxing’ itself. Instead, your liver and your kidneys are the way in which your body gets rid of toxins.


So, here’s why everyone keeps saying ‘every month’ – it’s because the average menstrual cycle is about one month, or 28 days long. However, only about 15% of women actually have a textbook 28-day cycle. Anything between 21-35 days is considered ‘normal’, but let’s use this ‘average 28-day cycle’ as an example for me to explain what’s going on week by week.

Good Vibes


Day 1 of week 1 is the first day of your period. Bleeding tends to last between 3-7 days. It’s not all just blood, there is also mucus, old cells from the lining of the uterus, as well as a surprising amount of water. As bleeding begins to slow down it will become darker, eventually turning brown. This is just the normal colour change of blood as it ages and breaks down so is nothing to worry about.

Good Vibes


Hormone production from the brain has begun to signal to the ovary that it’s time to start prepping an egg for ovulation. They also produce oestrogen which helps the endometrium to start thickening in preparation for a fertilised egg to implant. There is a massive surge in a hormone called LH (luteinizing hormone) which leads to ovulation at the end of this week

Good Vibes


Ovulation marks the start of the luteal phase. Progesterone levels begin to rise and peak around 7 days after ovulation.

Good Vibes


If the egg that you released about 7 days ago isn’t fertilised, the progesterone production from the corpus luteum begins to slow down. This also leads to a steady decline in oestrogen levels. The growth of the thickened endometrial lining is no longer supported, and it will eventually begin to fall away. This is your next period!

Is my Period Normal?


A ‘normal’ period is one that is not too painful, not too heavy, and happens approximately once a month, typically lasting about 3-7 days. The first few days are usually the heaviest, and it’s not uncommon to get a few little clots, although not usually anything bigger than 2-3cm in size. As bleeding slows down it will become darker, even going brown which is completely normal.

It’s normal to get some pain, especially on the first day or two, and sometimes the day before bleeding starts. This is because your uterus has to contract or squeeze to give gravity a helping hand to get the blood out, so period pains are kind of like mini labour pains! These pains or cramps are usually in the lower abdomen, but you can also get them in your back or down your thighs because of the cross-communication of the nerves in your lower body.

It’s not just during your period that you can get pain. It can also be normal to get a little bit of an uncomfortable sensation on one side of your stomach at the time that you ovulate. In order to pop out an egg, the ovary has to make a little cyst (fluid-filled sac) which bursts in order to release the egg. This all sounds pretty terrifying, but it’s totally normal and healthy. However, when this happens it can cause this slightly discomfort that we call ‘ovulation pain’ or ‘mittleschmerz’.

End Period Shame
End Period Shame


Many people believe that anything that isn’t exactly 28 days is an irregular cycle. But this is not the case. As I mentioned before, anything between 21-35 days is considered a normal cycle length. An irregular cycle is one where you can’t really predict when your period is going to come, and there’s more than 10 days variation in the length.

The length of your menstrual cycle is dictated by multiple factors. If things are ticking along nicely, your brain should be releasing hormones that signal to your ovaries to mature an egg as well as to release oestrogen at specific levels at specific times, ultimately resulting in ovulation. You’ll then get your period about 12-14 days after that. If your cycle is longer or shorter than 28 days it is the first half of the cycle leading up to ovulation that will differ in length. Once you ovulate you will get your period in a maximum of 14 days because the corpus luteum has a maximum shelf-life of 14 days if the egg that is released does not get fertilised.

There are so many things that can get in the way of the timing of this accurately timed hormonal cycle. Lack of sleep, not eating enough, over-exercising, travel across time zones as well as psychological stress can all alter the signals between the brain and ovaries making periods irregular. Polycystic ovarian syndrome (PCOS) is one of the most common hormonal conditions that commonly causes irregular periods, and can also make them stop altogether for several months at a time.

What Should I Monitor If I Have Concerns About My Period?

Heavy bleeding can be a cause for concern. Not only is it troublesome in terms of going about your daily life, taking part in sports, and just generally having to constantly worry about whether you’ve leaked, it can cause anaemia. This means low haemoglobin levels in the blood, and whilst it can be a consequence of heavy bleeding, it can also be a cause. So definitely worth getting checked out because it’s usually easy to treat. There are also other underlying causes of heavy periods such as fibroids that may also warrant treatment. It’s always difficult to define ‘heavy bleeding’. The textbooks say anything over 80ml…but what does that even mean!? Heavy bleeding can be considered as anything that interferes with your physical or emotional wellbeing. Changing pads every 1-2 hours, and passing large blood clots (more than 2-3cm) is also a pretty good indicator that your bleeding is on the heavier side.


Prepare your facts

It can be a bit overwhelming when you go to see a doctor so it can be helpful to take a list of the main problems that you want to discuss and the questions that you want answering. Most doctors prefer when patients have their concerns listed out because that gives them a higher chance at being really efficient with the relatively short time that we have during the consultation, and they’re more likely to leave satisfied that their concerns were addressed. In many instances, it can also be really helpful if you’ve been using a period tracker to keep an eye of your cycles for the last few months, and how any symptoms you’ve had relate to your cycle.

Please don’t feel that you need to come to go the doctor with a diagnosis. With the increase in the availability of health information, a lot of people think they need to work out what may or may not be wrong with them before they go to see a doctor. You don’t have to put that pressure on yourself; it’s for you and your doctor to work out together. And don’t forget that they’ve heard it all before…there’s nothing to be embarrassed about, and to them it’s completely normal to discuss body parts and functions.

End Period Shame
End Period Shame

Will I need an examination?

Lots of people are scared that they’re going to have an embarrassing or painful internal examination. In the majority of cases you will be examined, but it’s not always necessary to do an internal examination and will very much be guided by the conversation that you have with the doctor. You should be given the option to have a nurse/chaperone present and you don’t have to consent to examination if you feel uncomfortable. You can still be examined if you’re bleeding, but a lot of patients prefer not to in that situation. That’s absolutely fine, but as doctors we’re totally used to it and not scared of blood, or any other bodily fluids for that matter.

You may also have blood tests or scans performed on the day, or arranged for a later day.

Premenstrual Syndrome and The Menstrual Cycle

What is Premenstrual Syndrome?

PMS stands for ‘Premenstrual Syndrome’. It is the term given to a collection of psychological and physical symptoms that occur during the luteal phase of the menstrual cycle (ie. the 14 or so days between ovulation and the start of your period). It’s incredibly common with at least 40% of people who have periods being affected, and up to 10% having very severe PMS symptoms that significantly impact on their relationships, work, education and social life, which is called Premenstrual Dysphoric Disorder (PMDD).

The psychological PMS symptoms are probably the ones that get the most airtime and include anxiety, depression, mood swings, and loss of confidence to name a few. The physical symptoms are maybe less well talked about but still very much felt by a LOT of women and these include breast tenderness, bloating, fluid retention, skin breakouts, nausea and headaches.

The timing factor is also important. If you have the symptoms at other times of the cycle that do not correlate with your luteal phase, it’s very unlikely to be PMS, and therefore you should speak to your doctor about other potential causes. And that’s another reason why I’m really keen to getting my patients to track their cycle. The patterns in your mood and wellbeing that you may be able to identify throughout your cycle are incredible!

End Period Shame
End Period Shame

What’s the difference between PMS and Menstrual Cramps?

Menstrual cramps, also called period pains/cramps, are the pains that you get during your period. In some women they can start a day or two before the actual bleeding starts, but generally they’re strongest on the first day or two of your period. PMS on the other hand, refers specifically to the symptoms that you get in the week or two before your period, such as those suggested above, and they tend to disappear pretty quickly when your period arrives. They are caused by release of prostaglandins, which are chemical messengers released to cause little contractions of the muscle in the wall of the uterus when it’s time for the lining of the uterus to shed to aid the lining on its way out. These prostaglandins also act on your bowel and it’s therefore quite common to notice a change in bowel habit around the start of your period, with some cramping, increase in bowel emptying or even loose stools.

How does Contraception Affect Your Cycle and Your Period?

Hormonal forms of contraception can all affect your periods, but usually in a positive way by making them lighter, shorter and less painful. It’s also worth pointing out that many people use hormonal contraception as a way of helping their period-related symptoms, including heavy, painful periods and to deal with PMS. So whilst the name ‘contraception’ denotes something that stops conception (ie. stops you getting pregnant) there are in fact other reasons to take it.

There are two types of contraceptive pill – the combined pill (containing synthetic oestrogen & progesterone) and the progesterone-only pill (I think you can work out what that contains…) Both tend to make periods less painful, lighter and shorter, and some women on the progesterone-only pill may also stop having periods altogether. They both work by halting ovulation (no egg, no chance of pregnancy) and so whilst you will still make your own hormones, this happens at lower levels with less extreme fluctuations, so they may help with PMS symptoms. The combined pill is also used by some women to improve their hormone-related skin issues such as acne. The contraceptive ring and patch are similar to the combined pill and will have similar effects on your periods and skin.

The contraceptive injection, implant and hormone coil (also known as IUS or intrauterine system) are all progesterone-based and are also more likely to stop your periods temporarily while you’re on them. If your periods stop when you’re on hormonal contraception this is not something to be concerned about. If you’re not keen on this (many women like some kind of bleed as a reassurance that they’re not pregnant) you should speak to your doctor and consider alternatives.

The copper coil (also known as the IUD or intrauterine device) doesn’t contain any hormones but can make your periods heavier and that’s the commonest reason to have it removed before its ‘expiry date’, but it shouldn’t affect the timing. It’s also common to get some spotting in the first few months. Other kinds of non-hormonal contraception include condoms, sterilisation and fertility awareness methods, and these do not have any impact on your periods.

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