How Long Does a Period Last? Normal Length, Amount and When to See a Doctor

In brief:

• A normal period lasts 2–7 days, most often 5 days (NHS).
• It is normal for a period to come every 21 to 35 days (NHS).
• The heaviest days are the first 2. On heavy days the blood is red; on lighter days it may be pink or brown (NHS).
• A period that lasts more than 7 days is a change you should tell a doctor about (NHS).
• According to NICE, heavy bleeding is measured not only by the amount but by how much it affects your life.

How long does a period last?

According to the NHS:

These ranges are wide because every woman's cycle is different. NICE asks doctors to take the natural variation in period length and amount of bleeding into account when assessing heavy bleeding, and to discuss this with the woman.

The length of your period can change over your life. According to the NHS, periods can be heavier in the first years after they start, after childbirth and as you approach menopause. If your period gets longer or the bleeding gets lighter, it is not always a problem, but the cause should be looked into (NHS).

Why does the colour of period blood change?

According to the NHS, the blood is red on the heaviest days. On lighter days it may look pink or brown. We explain in detail what the colour tells you in What Does Period Blood Colour Mean?. Brown spotting before or after a period is covered in What Causes Brown Discharge?.

What is heavy menstrual bleeding?

According to the NHS, your periods may be heavy if:

• You need to change your pad or tampon every 1–2 hours, or empty your menstrual cup more often than recommended
• You need to use a pad and a tampon together, two products at the same time
• Your period lasts longer than 7 days
• You pass clots larger than about 2.5 cm
• Blood leaks onto your clothes or bedding
• You avoid daily activities such as exercise, or take time off work, because of your period
• You often feel tired or short of breath

According to the NHS, heavy periods are normal for some women. NICE also says heavy menstrual bleeding can deeply affect a woman's quality of life and that treatment should aim to improve quality of life rather than only the amount of bleeding.

Why might a period last longer or be heavier?

According to the NHS, heavy menstrual bleeding can sometimes be caused by:

• Conditions affecting the womb or ovaries: PMOS (formerly PCOS), fibroids, endometriosis, adenomyosis and pelvic inflammatory disease
• Conditions that make bleeding easier, such as von Willebrand disease
• Some medicines and treatments, such as blood thinners and chemotherapy medicines

According to the NHS, it can rarely be a sign of womb cancer. That is why it is important to tell a doctor about bleeding that changes its pattern or affects your life.

Can heavy bleeding cause iron deficiency?

It can. According to the NHS, heavy periods are one of the most common causes of iron deficiency anaemia. NICE recommends a full blood count for every woman with heavy menstrual bleeding. We explain the symptoms of iron deficiency in Iron Deficiency Symptoms.

Which product can I use?

The NHS lists three main period products: pads, tampons and menstrual cups. Pads come in many sizes; you can choose according to whether your flow is heavy or light. Panty liners are for days when your period is very light (NHS). How often to change a pad is covered in Can You Use Panty Liners Every Day? How Often Should You Change a Pad?.

When should you see a doctor?

According to the NHS, see a doctor if:

• Your period lasts longer than 7 days
• Heavy periods are affecting your life or have been going on for a while
• You have severe pain during your period
• You bleed between periods or after sex
• You have heavy periods together with pain when peeing, pooing or having sex
• Your periods have become irregular

Any bleeding after menopause should also be checked by a doctor (NHS).

Frequently asked

Is a 3-day period normal?

Yes. According to the NHS, a period can last between 2 and 7 days. A 3-day period is within this range. If your period has always been like this and is regular, being short is not a sign of a problem on its own. If the pattern has changed, tell your doctor (NHS).

What should I do if my period lasts 10 days?

A period that lasts more than 7 days means you should see a doctor (NHS). The doctor will listen to you to understand the cause, examine you if needed and order a blood test (NICE).

Are period clots normal?

Small clots can happen. The NHS lists clots larger than about 2.5 cm among the signs of heavy menstrual bleeding. If you often pass large clots, tell your doctor.

Is bleeding heaviest on the first day of a period?

According to the NHS, bleeding is usually heaviest in the first 2 days.