There are many reasons why a woman may miss her usual monthly period, or why periods might stop altogether.
Most women have a period every 28 days or so, but it's common to have a slightly shorter or longer cycle than this (from 24 to 35 days).
Some women don't always have a regular menstrual cycle. Their period may be early or late, and how long it lasts and how heavy it is may vary each time.
This page covers:
Why your periods might stop
There are a number of reasons why your periods can stop. The most common reasons are:
- sudden weight loss
- being overweight or obese
- extreme overexercising
- taking the contraceptive pill
- reaching the menopause
- polycystic ovary syndrome (PCOS)
It might be that your period is simply late, so you could wait a few days to see if it arrives. If it doesn't arrive, you can do a pregnancy test to confirm whether or not you're pregnant.
It's important to be aware that you can get pregnant in the days after your period is normally due. This can happen if the release of an egg (ovulation) is delayed - for example, as a result of illness or stress.
If you're stressed, your menstrual cycle can become longer or shorter, your periods may stop altogether, or they might become more painful.
If you're finding it hard to cope with stress, cognitive behavioural therapy (CBT) may be recommended. CBT is a talking therapy that can help you manage your problems by changing the way you think and act.
Sudden weight loss
Excessive or sudden weight loss can cause your periods to stop. Severely restricting the amount of calories you eat stops the production of hormones needed for ovulation.
Your GP may refer you to a dietitian if you're underweight, where you have a body mass index (BMI) of less than 18.5. The dietitian will be able to advise you about how to regain weight safely.
Being overweight or obese
Being overweight or obese can also affect your menstrual cycle. If you're overweight, your body may produce an excess amount of oestrogen, one of the hormones that regulate the reproductive system in women.
The excess oestrogen can affect how often you have periods, and can also cause your periods to stop.
The stress that intense physical activity places on your body can affect the hormones responsible for your periods. Losing too much body fat through intense exercise can also stop you ovulating.
You'll be advised to reduce your level of activity if excessive exercise has caused your periods to stop.
If you're a professional athlete, you may benefit from seeing a doctor who specialises in sports medicine. They'll be able to give you advice about how to maintain your performance without disrupting your periods.
You might miss a period every so often if you're taking the contraceptive pill. This isn't usually a cause for concern.
However, your periods should return when you stop using these types of contraception.
You may start missing periods as you approach the menopause. This is because oestrogen levels will start to decrease, and ovulation will become less regular. After the menopause, your periods will stop completely.
The menopause is a natural part of the ageing process in women, which usually occurs between the ages of 45 and 55. The average age for a woman to reach the menopause is 51 in the UK.
However, around 1 in 100 women experience the menopause before the age of 40. This is known as premature menopause or premature ovarian failure.
Polycystic ovary syndrome (PCOS)
Polycystic ovaries contain a large number of harmless follicles, which are underdeveloped sacs in which eggs develop. If you have PCOS, these sacs are often unable to release an egg, which means ovulation doesn't take place.
PCOS is thought to be very common, affecting about 1 in every 10 women in the UK. The condition is responsible for as many as one in three cases of stopped periods.
When to see your GP
See your GP if you're not pregnant - you've had a negative pregnancy test - and you've missed more than three periods in a row.
If you're sexually active and you haven't taken a pregnancy test, your GP may advise you to take one.
They may also ask you about:
- your medical history
- your family's medical history
- your sexual history
- any emotional issues you're having
- any recent changes in your body weight
- the amount of exercise you do
Your GP may recommend waiting to see whether your periods return on their own. In some cases you may need treatment for your periods to return.
You should also see your GP if your periods stop before you're 45 or you're still bleeding when you're over 55.
Referral to a specialist
If your GP thinks an underlying medical condition might have caused your periods to stop, they may refer you to a specialist.
Depending on what your GP suspects is causing the problem, you may be referred to:
- a gynaecologist - a specialist in treating conditions that affect the female reproductive system
- an endocrinologist - a specialist in treating hormonal conditions
You may have a full gynaecological examination and various tests, including:
- blood tests - to see whether you have abnormal levels of certain hormones, such as prolactin, thyroid-stimulating hormone, follicle-stimulating hormone, or luteinising hormone
- an ultrasound scan, CT scan or MRI scan - to identify any problems with your reproductive system or the pituitary gland in your brain
Treating underlying conditions
If test results indicate an underlying medical condition has caused your periods to stop, you may be offered treatment for your condition.
For example, if the cause is PCOS, you may be advised to take the contraceptive pill or tablets containing a hormone called progesterone.
Read more about the treatment of PCOS.
If the cause is early menopause (premature ovarian failure), this means the ovaries no longer function normally. Hormone medication is usually recommended. Treatments to try include the contraceptive pill or hormone replacement therapy (HRT).
If you have an overactive thyroid gland, you may be given medication to stop your thyroid gland producing too many hormones.
Read more about treating an overactive thyroid gland.
Article provided by NHS Choices