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Understanding your periods: what is typical, what to track and when to get help

By Kerri Hopkins · 4 min read · 20 October 2026

Your period is one of the clearest signals your body gives you. Knowing what is typical for you makes it easier to spot a change and to have a good conversation with your GP.

What is typical

• Periods usually come every 28 days or so, but anywhere from 21 to 35 days is common.
• Bleeding usually lasts 2 to 7 days, often around 5, and is usually heaviest in the first couple of days.
• Blood can be red, pink or brown.

Most people start their periods around age 12, though some start as early as 8. Early periods are often irregular, and it can take some months for a pattern to settle.

Iron, from the very beginning

Blood contains iron, so each period uses up some. The NHS lists women who lose a lot of blood in their periods as being at higher risk of iron deficiency anaemia, and heavy periods and pregnancy as very common causes of it. The NHS gives the recommended amount for women aged 19 to 49 as 14.8mg of iron a day.

• Iron-rich foods include red meat, beans, lentils, nuts, dried fruit, dark green leafy vegetables and fortified cereals.
• Tea, coffee and dairy can make it harder to absorb iron, so some people leave a gap between them and iron-rich meals.
• Check with your GP or pharmacist before taking iron tablets. The NHS says supplements of 17mg a day or less are unlikely to cause harm, and doses of 20mg or more can cause side effects.

Common signs of low iron include tiredness, breathlessness, a racing heartbeat, paler skin and headaches. If you feel like this, ask your GP about a blood test.

Why track your cycle

Noting the dates your period starts and stops, how heavy it is, any pain and how you feel gives you a clear picture over time. It makes changes easier to notice and gives your GP something concrete to work from. A simple notes app or calendar is enough.

Heavy periods

The NHS says you may have heavy periods if you:

• need to change a pad or tampon every 1 to 2 hours
• use two products at once
• bleed for more than 7 days
• pass clots larger than about 2.5cm (a 10p coin)
• bleed through to clothes or bedding
• feel tired or short of breath

Heavy periods can be normal for some people, but they are worth discussing if they affect your daily life. There are effective treatments, and your GP can check for causes such as fibroids, endometriosis or a bleeding disorder.

The government's renewed Women's Health Strategy (April 2026) describes heavy or painful periods as a “missed vital sign”, and says they can be a clue to anaemia, iron deficiency, endometriosis or fibroids. It proposes routine questions about your periods and how they affect daily life. So if someone asks, or you raise it yourself, you are doing exactly what the strategy wants.

When to see your GP

• Heavy periods that affect your life, or that have lasted a while
• Severe pain with your periods
• Bleeding between periods or after sex
• A change in your periods, such as lasting longer or getting lighter
• Any bleeding after the menopause
• Having missed three periods in a row with negative pregnancy tests
• Periods not started by 15 (or 13 with no other signs of puberty)

After having a baby

Bleeding after birth is heavy at first and carries on for a few weeks, gradually turning brown and lighter. Tell your midwife if you pass large clots. Very heavy or sudden bleeding, especially if you feel faint or your heart is racing, needs help straight away from your midwife, health visitor or GP.

Periods return at different times. If you bottle feed they may come back around 5 to 6 weeks after birth, and if you fully breastfeed they may not return until you cut back. You can get pregnant again as early as 3 weeks after birth, so start contraception within 21 days.

Perimenopause and menopause

Perimenopause is a natural stage of life that usually affects women between 45 and 55, though it can start sooner. Changes to your periods are often the first sign. They may become more or less frequent, and heavier or lighter, before stopping altogether.

See your GP if you still have periods but are bleeding more than before. See them too if you have gone 12 months without a period and then have any bleeding. The NHS advises keeping up contraception for 2 years after your last period if you are 40 to 49, and for 1 year if you are 50 or over.

Sources

NHS: Periods · NHS: Heavy periods · NHS: Iron deficiency anaemia · NHS: Iron · NHS: Perimenopause symptoms · NHS: Your body after the birth · NICE: Heavy menstrual bleeding (NG88) · GOV.UK: Renewed Women's Health Strategy for England (April 2026)

BioHer provides educational information only. It is not medical advice, diagnosis or treatment, and it does not replace your GP or other healthcare professional. If symptoms feel urgent or severe, call 111 for urgent advice, or 999 in an emergency.