What you need to know about period health

Menstrual cycle and patterns

A menstrual cycle starts on the first day of bleeding and ends the day before your next period begins. For most people, a typical menstrual cycle lasts around 28 days, but a cycle ranging between 21 and 35 days is generally considered normal.  

A normal menstrual period length typically lasts between 2 and 7 days, and the bleeding tends to be heaviest in the first 2 days. 

During the heaviest part of your period, the blood will be bright red, and on lighter days, the colour may be pink or brown.  

During your period, you will lose approximately 20ml to 90ml of blood (equivalent to 1 to 5 tablespoons). Some women bleed more heavily than this. 
 
It’s helpful to understand the different stages, such as the luteal phase length (the time between ovulation and your period), spotting vs light periods, and late/early period causes as these can all give important insight about your health. 

Tracking and interpretation 

Knowing how to track periods is a powerful tool for recognising any changes. Whether you note down your periods in a diary or use an app to keep track, it can help you understand what’s normal for you or know when to see a GP.

Ovulation vs menstruation: cycle phases explained  

Menstrual phase: The menstrual phase is the first stage of the menstrual cycle. It’s also when you get your period.  

Follicular phase: The follicular phase starts on the first day of your period (so there is some overlap with the menstrual phase) and ends when you ovulate.  

Ovulation phase: Ovulation is when your ovary releases a mature egg. This phase is the time during your menstrual cycle when you can get pregnant.   

Luteal phase: After the egg is released, the follicle transforms into the corpus luteum. This structure releases progesterone and oestrogen, keeping the uterine lining thick and ready for a fertilised egg. If pregnancy doesn’t occur, the corpus luteum shrinks and hormones drop. This is when you may experience premenstrual syndrome (PMS).  
 

Period pain symptoms and relief

Hormonal changes in the lead-up to your period can cause both physical and emotional symptoms, although not everyone is affected. This is known as premenstrual syndrome (PMS), also called premenstrual tension (PMT). You might notice symptoms such as:  

• Headaches 

• Tender or sore breasts 

• Tiredness 

• Feeling irritable  

• Bloating 

• Changes in mood 

• Low sex drive 

• Spots developing 

Over-the-counter products can help to give period pain relief at home for symptoms such as headaches. For those who experience migraine with periods, prescription medicine may be recommended. Self-care, including regular exercise and relaxation, can help with emotional changes such as low mood.  

What causes period cramps?

Period cramps happens when the muscles in the womb tighten or contract. These muscles are contracting all the time, but they are so mild that they go unnoticed. During a period, the muscles in the womb contract more intensely to help shed the womb lining as part of the menstrual cycle. The womb also releases chemicals called prostaglandin making the contractions even stronger and triggering more pain. Some women experience severe cramps (dysmenorrhoea) along with heavy bleeding (menorrhagia) and clots.

The causes of irregular periods

Throughout your life, your periods may change, for example, they may become lighter, heavier, or they may become irregular for a time. This doesn’t necessarily mean there’s cause for concern, but you can talk to your GP if you are worried about any changes. If you have bleeding between periods, notice bleeding after sex, or bleeding after menopause, you can make your GP aware so they can investigate the cause.  

Conditions that can impact menstrual health

There are several medical conditions that can affect your periods, some of which may require further medical attention. These include endometriosis and polycystic ovary syndrome [PCOS].  

Endometriosis

A condition estimated to affect 1 in 10 women in the UK where cells similar to those in the lining of the womb (uterus) grow in other parts of the body, endometriosis can impact daily life and it may cause severe period pain, heavy periods, and pain when you go to the toilet. You may also have extreme tiredness and experience pain during or after sex. Talk to your GP if you think you might have endometriosis, as they can advise how best to manage it and what possible treatment options are available. You’ll also find lots of support and information at the UK charity website, Endometriosis UK.  

Polycystic ovary syndrome [PCOS]

PCOS is a common condition (the NHS estimates approximately 1 in 10 women live with PCOS) that affects how a woman’s ovaries work.  

The main signs of PCOS are:  

• Irregular periods - where your ovaries do not regularly release eggs (ovulation)  

• Amenorrhoea - where your periods may stop altogether 

• Excess androgen - higher than normal levels of hormones such as testosterone in your body, which may cause physical signs such as excess facial or body hair  

• Polycystic ovaries – your ovaries become enlarged and contain fluid-filled sacs (follicles) that surround the eggs   

You may be diagnosed with PCOS if you have at least two of these features. Common PCOS cycle changes can include symptoms like irregular or absent periods, along with trouble getting pregnant, increased hair growth on the face or body, weight gain, thinning hair, oily skin, or acne. The exact cause of PCOS is unclear, but it can run in families. Although there isn’t a cure for PCOS, its various symptoms can be managed. Talk to your GP if you think you may have PCOS or learn more on the NHS website.

Your thyroid and periods

Your thyroid gland plays a crucial role in controlling your metabolism, and its hormones are closely linked to your reproductive system. When your thyroid produces too much (hyperthyroidism) or too little of these hormones (hypothyroidism), it can directly impact your menstrual cycle. This can lead to various period issues like irregular periods, heavy bleeding, missed periods, or even stopping periods altogether, as the imbalance disrupts the delicate hormonal signals needed for a regular cycle. Talk to your GP if you think you may have thyroid problems or learn more about hyperthyroidism and hypothyroidism on the NHS website.

Lifestyle and diet

Focusing on a balanced diet for menstrual health and limiting your intake of alcohol and/or caffeine can be beneficial in helping you feel nourished and energised throughout your cycle. If you experience heavy bleeding, discussing the possibility of an iron deficiency from heavy periods with your pharmacist or GP can help in making sure your body is getting what it needs. It’s a common myth that you can’t exercise on period days, but gentle exercise can help ease period pain and release endorphins that help you to feel good. 

Period products

Period products absorb the blood released during your period. There are a variety of products to choose from, including pads, tampons, a menstrual cup, or reusable period pants. Each one is a matter of personal preference. You might want to try different options before you settle on the one that works best for you. Whatever products you choose, it’s important to change them regularly to maintain good hygiene. 

Pads vs tampons

Pads are worn externally, adhering to underwear, and are generally easy to use, making them a good choice for lighter flows or overnight protection. Tampons are inserted internally, often offering discreet protection, and are ideal for active lifestyles, such as swimming on period days. Both come in various absorbencies. It’s a matter of personal preference and what feels most comfortable and secure for you.  
 
Toxic shock syndrome (TSS) is a rare but very serious condition caused by bacteria, sometimes linked to tampon use, especially if absorbent tampons are left in too long. To reduce your risk, always use the lowest absorbency tampon for your flow and change it regularly (every 4-8 hours).