Periods: what is normal and when to see a GP

What does a normal period look like?

A period is the time in the menstrual cycle when the womb lining is shed and leaves the body as blood. If an egg is not fertilised, the levels of the hormones oestrogen and progesterone fall.

The NHS says the average menstrual cycle is about 28 days. It also describes regular cycles of 21 to 35 days as normal. NI Direct, the Northern Ireland government health service, says a period usually lasts 2 to 7 days. Sources vary a little on the exact ranges, so the numbers are a guide and not a strict rule.

What counts as an irregular period?

NHS 111 Wales says periods are usually called irregular when the gap between them is under 21 days or over 35 days. The NHS says irregular can also mean a change in how much blood is lost or in how long bleeding lasts.

The NHS names several common causes. These include puberty, the years around the menopause, pregnancy and changing hormonal contraception. NI Direct also lists stress, sudden weight loss or gain and over-exercising as common reasons for missed or changed periods. The NHS also names polycystic ovary syndrome and thyroid problems as possible causes.

When do periods or bleeding between periods need a GP?

The NHS lists periods lasting longer than 7 days and bleeding between periods as reasons to see a GP. It also lists periods that have become irregular, and difficulty getting pregnant. NHS Inform advises contacting a GP about bleeding between periods or after sex, and about periods that come closer together or further apart than usual. It adds that cancers of the womb or cervix can, in rare cases, cause bleeding between periods, which is one reason it is worth having checked.

The NHS describes signs of heavy bleeding, such as passing blood clots larger than about 2.5 centimetres and needing two types of period product at the same time. Heavy periods are covered on their own page on this site.

When is period pain a reason to see a GP?

NI Direct says period cramps are usually caused by the womb muscle tightening, and that the womb wall contracts more strongly during a period to help the lining shed. It lists hormonal contraception, exercise and over-the-counter painkillers such as ibuprofen or paracetamol among the things that can ease the pain. It advises seeing a GP if the pain is so severe that it affects daily life.

Period pain that disrupts daily activities is also one of the symptoms NICE lists as a reason to suspect endometriosis. The NHS advises seeing a GP about possible endometriosis symptoms, especially if they have a big impact on life, and says it may help to write the symptoms down first. A GP may refer someone to gynaecology if initial treatment does not work or is not tolerated. A normal ultrasound scan does not rule endometriosis out.

Which pelvic pain needs urgent help?

NHS 111 Wales advises asking for an urgent GP appointment, or getting help from NHS 111, if pelvic pain is severe, getting worse, or hurts when moving or touching the area. The same page lists difficulty passing urine or opening the bowels, a very high temperature and pregnancy as other reasons for urgent help.

NHS 111 Wales says a few conditions that cause pelvic pain need emergency treatment, such as appendicitis and peritonitis. It describes NHS 111 as the service for when medical help is needed fast but it is not a 999 emergency. Emergencies are for 999.

What if periods stop, or have not started?

NI Direct and the NHS advise seeing a GP when someone is not pregnant, has had a negative pregnancy test and has missed more than 3 periods in a row. NI Direct lists pregnancy, stress, sudden weight loss and over-exercising among the common reasons for missed periods.

For periods that have not started, the NHS says to see a GP if they have not begun by the age of 15. NHS 111 Wales gives 15, or 13 if there are no other signs of puberty. NHS Inform puts it at around 16. Reasons for a delayed start include being underweight, intense exercise, severe stress, an eating disorder, hormone problems and medical conditions. NHS Inform notes that some people start their periods later than others, and that this can be normal. A GP will typically ask about health and may arrange blood tests to find the cause.

What helps before a GP appointment, and what about premenstrual symptoms?

NHS 111 Wales suggests that before seeing a GP about period problems, it can be useful to keep a diary of symptoms through the menstrual cycle. This gives the doctor a detailed picture of what happens, and when. Using an app or a diary to track periods can also show whether cycles are irregular.

NI Direct links premenstrual syndrome to shifting hormone levels across the cycle. Symptoms such as mood changes, irritability, headaches, tiredness, bloating and breast tenderness usually start in the two weeks before a period and ease once it starts. Not everyone has them. A more severe form, premenstrual dysphoric disorder, can disrupt daily life.