Your Menstrual Cycle: Unpacking The Four Phases

At Lena, we believe that our wombs are a source of infinite wisdom. Each month, each phase of our cycle delivers a sort of report card on your hormones, your stress levels and your vaginal health. But if you don't know how to read that report card, you are left feeling confused, lost and disconnected from your own body. We're here to change that and teach you the language of your menstrual cycle. In this article: understanding your cycle, working with the phases and championing your hormonal health.

To fully understand your menstrual cycle, we need to know and understand the following:

What is the menstrual cycle, and what is its purpose?
What is the function of my sex hormones and how do they change throughout the month?
What are the different phases of the cycle and how does this impact my mood, energy levels, physical symptoms and relationships with others?

The Menstrual Cycle: What Is It And Why Does It Exist?

The menstrual cycle is a monthly series of hormonal and physiological changes that occurs in the female body, preparing for a potential pregnancy.

Humans have a biological drive to want to reproduce and we have the sex organs, sexual desire and social structures which enable us to conceive, grow and raise offspring. Each month, when your ovaries release an egg, when oestrogen builds the endometrium and progesterone maintains it, your body is working for one thing and one thing only: pregnancy. It does not matter if you don't want to get pregnant now, or in the future, that is what your body is trying to do each month.

The release of an egg is your body's way of improving the chance at reproduction and therefore the survival of DNA and the continuation of life. Understanding this is not supposed to guilt you into thinking you should get pregnant, it is simply to explain why it happens each month and that your body is not against you or trying to make you go through hell every 28 days. It is just trying to make a pregnancy possible, should you want it.

What Is The Role Of Hormones In The Menstrual Cycle?

I recommend reading our most recent article on the Lena Blog, Hormones: What They Do, How They Work and How To Harness Their Power. Inside this article, you'll find everything you need to know on the role of oestrogen and progesterone in reproduction and for the rest of your body too.

The Different Phases Of The Cycle

You can split the menstrual cycle into four phases (menstrual, late-follicular, ovulatory, luteal), or you can split it into 2 broader phases (follicular and luteal). As a practitioner, I lean more towards the four phase model because there are key differences between each and I think it helps to validate that we really can feel different from week to week.

In the first part of the cycle, oestrogen is the dominant hormone. The role of oestrogen here is to build the endometrium (the lining of your womb) and to ensure the egg is released so that a pregnancy is possible in the first place. For the first half of the cycle, oestrogen contributes to rising confidence and sociability, which is to increase the likelihood that we will have sex to reproduce. You might find it easier to start projects or focus on tasks during this time, as your energy is higher and you are able to take more risks.

In the second half of the cycle, progesterone is the dominant hormone. The role of progesterone here is to maintain the endometrium and to support your body in case of a pregnancy. Progesterone is the protecting hormone and in the luteal phase it interacts with the amygdala (the fear centre in the brain) to make you more acutely aware of threats in your environment. This is your body's way of trying to keep you and a potential pregnancy safe. We aren't hunter-gatherers anymore, so we don't have to worry about a lion coming to eat us. Instead, this might feel like being more emotionally sensitive to others - quicker to react, irritable or taking fewer risks.

From the graph below, we can see that oestrogen rises in the first half of the cycle then dips throughout the luteal phase. There is a mini-peak in the luteal phase, which is your body's last-minute attempt in trying to promote a pregnancy. You might feel a mid-luteal surge of energy because of this.

Progesterone is low in the first half of the cycle, then it rises steadily in the luteal phase, before plummeting at the end of the luteal phase. It is the drop in progesterone that stimulates the uterus to begin shedding, which then arrives as your period a few days later.

A graph showing the rise and fall of key sex hormones across the menstrual cycle.

Image credits: Fity.Club

Menstruation (Days 1-5)

Let's start at the start. Day 1 of your cycle is Day 1 of your period.

At the start of the cycle, both oestrogen and progesterone levels are low and so you can feel tired, less sociable, like you want to wrap up warm and stay home, eat comforting foods and do activities that feel familiar.

At a biological level, your body is recovering from an enormous drop in progesterone, one study found that in healthy individuals, progesterone levels can vary up to 8-fold in a 90 minute period - that's one of the largest hormonal drops in human physiology. Feeling like you want a bit of you time is very understandable, and we encourage taking extra time for you during your period wherever possible.

Our periods deliver arguably the largest part of the report card as the colour, consistency, amount and smell of your blood are key indicators of menstrual health. As well as this, we may experience cramping, breast tenderness, digestive issues and skin changes, as well as other symptoms that can feel disconnected.

So what information can you take from menstruation?

The length of your period: it should last between 3-7 days, starting heavy and then becoming lighter as the days go on.
The colour of your blood: it should be bright red, with minimal clots (if you regularly have clots bigger than a garden pea, this should be investigated). If your period blood is light in colour (like watermelon-pink) it could mean that your oestrogen levels are low. Alternatively, brown blood should be investigated for low progesterone levels, or high oestrogen levels.
The amount of blood: around 30-50ml of blood loss is normal. If you'd like to learn what that means in terms of menstrual cup/pads/tampon use, you can find the answer in this Lena article.
If there is a metallic smell: this is the smell of iron-rich blood, which is not actually something to worry about.
If there is a fishy smell: this could be a sign of Bacterial Vaginosis, which is a condition of bacterial overgrowth in the vagina. It's common and very treatable, so it's worth speaking to your doctor about this as soon as you can. You may also spot gray discharge in the rest of your cycle.
If you spend the first few days unable to leave the toilet, it's likely that your prostaglandin levels are high. The period poos are not an uncommon phenomenon, but that doesn't make it normal. High levels of stress and inflammation in the body can cause an overproduction of prostaglandins (PGs), which are hormone-like substances. High levels of PGs can intensify period cramps and the need to pass stool (poop!).

If you dread the arrival of your period each month, we need to talk. Your period should not cause excessive discomfort that requires days of painkillers to get through, or forces you to take days off work, or means you're bleeding through pads and tampons every hour. If this sounds like you, speak to a doctor or women's health practitioner as you may have an underlying condition that needs attention.

Looking to support your menstruation phase? We have a whole separate article on How To Make Your Menstrual Cycle Your Superpower, where you'll find tips and tricks on supporting each of the phases.

The Late Follicular Phase (Days 5-13)

The first half of the cycle is known as the follicular phase, with the menstruation phase being included within the follicular umbrella. When your period finishes, you enter the later follicular phase. Described by many as "your inner Spring", rising oestrogen and testosterone levels can improve your energy levels, sociability, productivity, sexual desire and you may even notice that your hair feels smoother or your skin looks better. This is all thanks to oestrogen!

During this phase, we may be open to taking more risks and we may find that we're able to stay focused on tasks. You may also find that your creativity is heightened, so it's a good opportunity to make the most of this energy or start a new venture. I'm always cautious to glamorise one phase over another, because I believe each can be enjoyed individually for the different characteristics that it brings. Enjoy the rising energy and sociability you have here, particularly if you find that your energy dips in the later part of the month.

The Ovulatory Phase (Days 13-15)

The ovulatory phase is defined by the event of ovulation, which is the release of en egg from its follicle, stimulated by a surge in Luteinising Hormone (LH) and occurring roughly on Day 14 of the menstrual cycle. Described by many as "your inner Summer", it is a time in which the majority of women feel their most confident, energetic and productive. The peak in oestrogen and testosterone cause heightened sexual desire and you may find you have more energy and confidence to engage in sex too.

Not all women feel this way during their ovulation, which is okay, as we are all different. Some feel their best or most confident at other stages of the month, some feel a steady confidence through the month. For some of us, each month can feel different from the other. What I try to emphasise is that understanding your cycle and your hormones can help you make sense of these changes and why you might be feeling more introspective, more irritable, less sociable, more or less interested in sex, etc.

The Luteal Phase (Days 16-28)

The luteal phase is the phase that follows ovulation, lasting around 12 days and ending with the arrival of your period. The luteal phase is known as "your inner autumn" and women can experience any of the following:

More introspective or reflective nature: wanting to be alone, less interested in social engagements, reflecting back on the last few weeks and analysing your relationship, friendships and how you've been feeling.
Feeling more relaxed or sleepier: as progesterone rises, we feel its brain-boosting benefits.
Heightened emotional sensitivity: perhaps you feel less patient than usual, or you feel irritated by things which normally wouldn't bother you.
Feeling hungrier: during the luteal phase, our metabolic rate increases and we actually need around 150 extra calories a day to feel satiated.
The arrival of Premenstrual Syndrome (PMS): tender breasts, headaches, mood changes as described above, bloating or digestive issues etc. Over 90% of women will experience some form of PMS at some stage in their life, but it's important to note that PMS that disrupts your life is not normal and should be investigated.

The luteal phase is an incredible time to turn inward and really understand how you're feeling. Rising progesterone levels support sleep and mood in the second half of the cycle, which should bring a sense of relaxation. This is not accidental - it is your body's way of trying to get you to slow down, sleep a little bit more and protect your energy. As I mentioned above, your body is trying to support a potential pregnancy and so it wants to keep you away from threats and it wants you to conserve your energy stores.

I hope we can shift the narrative away from demonising the luteal phase. It is just as important and valuable to your body and mind as the first half of the cycle, and it brings with it incredible benefits in protecting your brain, as well as reducing too much growth in your breast and uterine tissue.

To summarise...

Women experience four unique different phases across a roughly 28-day period.
Hormones exist in flux, they are rising and falling throughout the month which contributes to changes in mood, sleep, sexual desire, energy levels, sleep and hunger needs.
Each of the phases is equal in value to your body and mind.
It's okay to feel differently at different times of the month.
We can use the menstrual cycle to understand what it is happening inside of our bodies each month: stress levels, inflammation, bacterial growth, hormone levels.

If you'd like to learn how you can harness your menstrual cycle, check out this article: How To Make Your Menstrual Cycle Your Superpower.

Written and edited by Dr Rachel Denham, a trained medic and Women's Health Practitioner, who has worked across the charity and humanitarian sector and now specialises in women's health. Rachel is the creator of Bloody Nora, a women's health and wellbeing zine that fuses storytelling, art and science.

Sources:

https://pmc.ncbi.nlm.nih.gov/articles/PMC4436586/
https://www.ncbi.nlm.nih.gov/books/NBK279054/
https://www.drlouisenewson.co.uk/podcasts/sarah-hill