There are many reasons why a woman may miss her period, or why periods might stop altogether.
Most women have a period every 28 days or so. It's common to have a shorter or longer cycle than this (from 21 to 40 days).
Some women do not always have a regular menstrual cycle. Their period may be early or late. How long it lasts and how heavy it is may vary each time.
Why your periods might stop
Common causes of periods stopping include:
- sudden weight loss
- being overweight
- doing too much exercise
- taking the contraceptive pill
- the menopause
- polycystic ovary syndrome (PCOS)
Periods can also stop as a result of a medical condition. These include heart disease, uncontrolled diabetes, an overactive thyroid, or premature menopause.
You might be pregnant if you're sexually active and your period is late. Pregnancy is a common reason why periods unexpectedly stop. It can sometimes happen if the contraception you're using doesn't work.
It might be that your period is just late. You could wait a few days to see if it arrives. You can do a pregnancy test to confirm if you're pregnant.
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.
If you're stressed, your menstrual cycle can:
- become longer or shorter
- stop altogether
- become more painful
If you're finding it hard to cope with stress, cognitive behavioural therapy (CBT) may help. 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. You're underweight if you have a body mass index (BMI) of less than 18.5. A dietitian will tell you how to regain weight safely.
If your weight loss is caused by an eating disorder, they may refer you to an eating disorder specialist.
Being overweight can also affect your menstrual cycle. Your body may produce an excess amount of oestrogen. Oestrogen is one of the hormones that regulate the reproductive system in women.
Excess oestrogen can affect how often you have periods. It can also cause your periods to stop.
Your GP may refer you to a dietitian if you're overweight and it's affecting your periods. The dietitian can talk to you about how to lose weight safely.
Doing too much exercise
Intense physical activity can place stress on your body. This can affect the hormones responsible for your periods. Losing too much body fat through intense exercise can stop you ovulating.
You'll be advised to reduce your level of activity if excessive exercise has caused your periods to stop.
You might miss a period every so often if you're taking the contraceptive pill. This is not usually a cause for concern.
Some types of contraception can cause periods to stop altogether.
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 your oestrogen levels start to decrease, and ovulation becomes less regular. After the menopause, your periods stop completely.
The menopause is a natural part of ageing in women. This usually happens between 45 and 55.
But around 1 in 100 women go through 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. These are underdeveloped sacs in which eggs develop. If you have PCOS, these sacs are often unable to release an egg. This means ovulation does not take place.
PCOS is very common, affecting about 1 in every 10 women in Ireland. The condition is responsible for as many as 1 in 3 cases of stopped periods.
When to contact your GP
Non-urgent advice: Contact your GP if:
- you're not pregnant
- you've missed more than 3 periods in a row
If you're sexually active and you have not taken a pregnancy test, your GP may get 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 weight
- the amount of exercise you do
Your GP may recommend waiting to see if your periods return on their own. In some cases you may need treatment.
You should also see your GP if your periods stop before you're 45 or if you're still bleeding when you're over 55.
Referral to a specialist
If your GP thinks a medical condition might have caused your periods to stop, they may refer you to a specialist.
Depending on what your GP thinks is causing the problem, you may be referred to:
- a gynaecologist – a specialist in treating conditions affecting the female reproductive system
- an endocrinologist – a specialist in treating hormonal conditions
You may have a gynaecological examination and various tests, including:
- blood tests – to see if you have abnormal levels of certain hormones
- 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 a medical condition has caused your periods to stop, you may need treatment for the condition.
If PCOS is the cause, you may need the contraceptive pill or progesterone (a hormone) tablets.
If early menopause (premature ovarian failure) is the cause, your ovaries are not functioning normally.
If you have an overactive thyroid gland, you may be given medication to stop your thyroid producing too many hormones.
Content supplied by the NHS and adapted for Ireland by the HSE