Explaining the menstrual cycle phases

Supporting your teen through them

Quick summary:

• The menstrual cycle has four phases: menstruation, follicular, ovulation, and luteal, each bringing hormonal changes that affect mood, energy, and the body
• Supporting a teen through these phases with rest, nutrition, and understanding can help them manage symptoms like PMS, cramps, and mood swings
• Encouraging your teen to track their cycle with luna’s period tracker can help them recognise patterns, prepare for changes, and feel more in control of their wellbeing

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A teen’s menstrual cycle is a natural process that their body goes through each month – this includes their period.

A full menstrual cycle begins on the first day of bleeding (the period) and ends the day before the next period starts.

The average menstrual cycle lasts 28 days, but it can be as short as 21 days, or as long as 35 days – each person’s will be different.

You may have heard about the menstrual cycle, and of periods, but but did you know that the menstrual cycle is made up of four key phases?

Each of the menstrual cycle phases has distinct hormonal changes that affect a menstruator’s mood, energy levels, and body.

Why is it helpful to know about the menstrual cycle phases?

We all want what’s best for our child, but it can be challenging to support them when their mood, energy levels, and physical symptoms fluctuate throughout the month. 

By understanding the menstrual cycle, you and your teen can recognise patterns, manage their emotions, and take control of their wellbeing. 

Knowing what’s happening in the body during each phase, can help you to help your teen  anticipate changes and develop strategies to feel their best during each phase.

What you’ll learn in this parent guide

This guide will break down everything you and your teen need to know about the menstrual cycle. 

We’ll explain the four phases and what happens during each one, highlight common symptoms, and provide practical ways to support your teen through the changes they experience.

What are the four phases of the menstrual cycle?

Understanding the menstrual cycle in this much detail isn't always covered in school, but it plays such an important role in our lives that we feel it should be talked about more.

The menstrual cycle is split into two main parts, or phases: 

• The follicular phase
• The luteal phase

These two phases are split roughly 50/50 time-wise.

You can remember this as follicular for first and luteal for last. 

Across these two main phases, there are four smaller phases that break the cycle down further. The part where they bleed – the period – is just the first part.

These four phases of the menstrual cycle are:

• Menstruation (a period)
• The follicular phase (the first half)
• Ovulation
• The luteal phase (the second half)

As mentioned early, the menstrual cycle starts on the first day of bleeding and finishes the day before the next period begins.

While the average cycle takes 28 days, it can be as short as 21 days and as long as 35 days – so it’s possible that this cycle, and so a period, can begin twice in the same month.

A deep dive into the 4 phases of the menstrual cycle

Phase 1: what happens during a period or the menstruation phase? 

Menstruation occurs between day 1-5 of the cycle, and is also a part of the follicular phase:

• The uterine lining sheds, leading to bleeding (your teen’s period)
• Hormone levels (oestrogen, progesterone, LH, and FSH) are at their lowest

What are the main symptoms of menstruation?

• Cramps and lower abdominal pain – these can also be felt in the lower back, thighs or bum
• Fatigue and low energy – if severe, this may be a sign your teen has heavier periods than normal
• Mood swings and emotional sensitivity
• Bloating, digestive discomfort and changes in bowel habit – diarrhoea or constipation
• Acne, spots and oily skin – a good teen-friendly skincare routine can help with this

Supporting your teen during their period

• Let them know it’s okay to rest when they need to, try to go easy on them during this time
• Make them a hot water bottle or offer to draw a warm bath to soothe cramps
• Make sure they’re eating iron-rich foods to help replenish nutrients – things like spinach or red meats if they eat meat
• Encourage self-care, like gentle exercise, journaling or getting an early night
• Validate their emotions during this time (they might not be feeling their best and might be a little sensitive)

Phase 2: what happens in the follicular phase?

This happens on day 1-14 of the cycle, and so it also includes their period:

• The follicular phase starts on the first day of menstruation and continues until ovulation
• Oestrogen levels rise at the end of and after the period ends, boosting energy, focus, and motivation
• The ovaries prepare to release an egg by maturing follicles

People often think of periods as a really tough time throughout, both emotionally and physically. This is true to a point. 

But as menstruators come to the end of their periods, they may find their energy levels are much better than at the start – thanks to the rise in oestrogen levels. And so actually, a period can improve as time goes on.

What are the follicular phase symptoms?

• Increased energy and motivation (this can increase as a period goes on)
• Improved concentration and focus
• More stable and positive mood
• Clearer skin due to rising oestrogen levels

Supporting your teen during the follicular phase

• Find ways to help them take advantage of this high-energy time e.g. schoolwork and sports
• Ensure they eat nutrient-rich foods, and focus on iron as well especially if still on their period
• Remind them that balance is key – rest is still important, especially when they’re still on their period, as they may have moments of feeling great and tire quickly again

Phase 3: what happens in the ovulation phase?

This happens on day 11-15 of the cycle, and so is part of the luteal phase:

• A mature egg is released from the ovary
• Oestrogen, testosterone, and luteinising hormone (LH) peak
• Some teens might experience mild cramps on one side of the abdomen – but if this is persistent or very painful, it could be related to something else in which case it’s important to see a doctor

Did you know that ovulation cramps – which aren’t talked about a lot – are known as mittelschmerz, or “middle pain”? It’s called this because it happens about midway through the menstrual cycle.

What are the ovulation symptoms?

• Increased confidence and sociability
• Higher energy levels
• Mild bloating or cramps
• A slight rise in body temperature

Supporting your teen during ovulation

• If they feel particularly outgoing or energetic, try to find ways to make the most of it with them e.g. social plans or fun bonding activities together (as they may be in a great mood!)
• If they experience ovulation pain, suggest gentle stretching or a warm compress – all the same things you can do to help relieve period pain
• If they are curious about why they ovulate, or if you think they may be sexually active, it may be a good time to start talking about reproductive health – luna’s got a guide to talking to your teen about sex if needed

Did you know that while someone is most likely to get pregnant during the ovulation phase, it’s possible to get pregnant through unprotected sex at any point during the menstrual cycle? Including during a period.

Phase 4: what happens in the luteal phase?

This happens on day 15-28 of the cycle, and so this phase also includes ovulation:

• After ovulation, progesterone increases to prepare the uterus for a possible pregnancy
• If pregnancy doesn’t occur, hormone levels drop, leading to pre-menstrual symptoms (PMS)

What are the luteal phase symptoms?

• Increased tiredness and a desire to slow down
• Bloating and digestive changes
• Emotional sensitivity and mood swings
• Stronger food cravings, particularly for carbohydrates and sweets
• Oilier skin, spots and acne – a good teen-friendly skincare routine can help with this

This phase isn’t talked about a lot, but can often be tougher even than a period phase for some menstruators. 

Knowing about it can help to explain those feelings in the lead up to a period and can even help us to be more aware of when our period is on the way (alongside using a period tracker).

Supporting your teen during the luteal phase

• Let them know it’s okay to set boundaries and take more time for themselves if they feel irritable or overwhelmed
• Remind them that they’re likely feeling this way because their period is coming soon
• Help them to stock up on any period products and things they might need to make their period easier e.g. snacks
• Validate their emotions – pre-menstrual syndrome (PMS) can make small things feel big, and so they may be more sensitive to things that seem a bit inconsequential to you in the moment

Tracking and understanding the menstrual cycle phases

Your teen’s period cycle phases won’t always be the same – while the average cycle lasts 28 days, some teens have shorter or longer cycles, and that’s completely normal. 

It’s also important to note that it’s normal for teens’ periods to be irregular when they’re new to them – their body is still getting used to having periods.

Encouraging your teen to track their period can help them understand their body better and prepare for what’s ahead.

Why should a teen use a period tracker?

• Helps them to spot patterns in their moods and symptoms
• Helps them to predict their period
• Helps them to prepare for good days and bad days during their cycle phases
• Helps them to feel in control of their emotions as they can understand why they’re feeling a certain way

You might want to encourage your teen to use luna’s period tracker to keep track of their cycle and learn more about how their body changes across the 4 phases of the menstrual cycle.

luna’s period tracker is designed specifically for teens to use, in collaboration with other teens and medical professionals, to make sure it’s age-appropriate, medically accurate and easy to use.

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Empowering your teen through their cycle

Your teen’s menstrual cycle phases are an important part of their health, and understanding them can help them feel more in control of their body and emotions. 

Each period phase is different, and learning to recognise hormonal changes can lead to better self-care and overall wellbeing.

By being informed and tracking their cycles, your teen can build a more positive relationship with their period. 

And with your support, they can learn that their cycle isn’t just something to deal with – it’s a powerful part of who they are!

Hopefully this article has helped you get to grips with all of this, and you feel more at ease going into a conversation with your pre-teen or teen about the menstrual cycle phases.