Heavy Periods (Menorrhagia)

heavy periods

Heavy periods are common. In most cases no cause can be found. In some cases a cause is found such as endometriosis, fibroids, and other conditions (listed below). In most cases treatment is effective by using medication to reduce bleeding, or by surgery.

What is a normal period, a heavy period, and menorrhagia?

About 1 in 3 women describe their periods as heavy. However, it is often difficult to know if your periods are normal or heavy compared with other women. Some women who feel they have heavy periods actually have an average blood loss. Some women who feel they have normal periods actually have a heavy blood loss. Most of the blood loss (about 90%) usually occurs in the first three days with either normal or heavy periods.

What is a normal period?

A normal period is a blood loss between 20 and 60 ml (4-12 teaspoonfuls). Bleeding can last up to eight days, but bleeding for five days is average.

What is heavy period?

A heavy period is a blood loss of 60-80 ml or more. This is about half a teacupful or more. However, it is difficult to measure the amount of blood that you lose during a period. For practical purposes, a period is probably heavy if it causes one or more of the following:

  • Flooding through to clothes or bedding.
  • You need frequent changes of sanitary towels or tampons.
  • You need double sanitary protection (tampons and towels).
  • You pass large blood clots.

What is menorrhagia?

Menorrhagia means heavy periods that recur each month. Also, that the blood loss interferes with your quality of life. For example, if it stops you doing normal activities such as going out, working or shopping. Menorrhagia can occur alone or in combination with other symptoms.

What are the reasons for recurring heavy periods?

The cause is not known in most cases

This is called dysfunctional uterine bleeding and is the cause of heavy periods in four to six out of ten cases. In this condition the uterus (womb) and ovaries are normal. It is not a hormonal problem. Ovulation is often normal and the periods are usually regular. It is more common if you have recently started your periods or if you are approaching the menopause. At these times you may find your periods are irregular as well as heavy.

A chemical called prostaglandin may play a part. The amount of prostaglandin in the blood may be different in women with heavy periods. The lining of your uterus is more sensitive to the effects of prostaglandin, which results in heavier periods. In some women, the blood vessels that supply blood to the lining of the womb are dilated (larger), which then results in the blood loss being heavier. This dilatation is also thought to be due to prostaglandins in the body.

Other causes

These are less common. They include the following:

  • Fibroids which are benign (noncancerous) growths in the muscle of the uterus. They often cause no problems, but sometimes cause symptoms such as heavy periods.
  • Other conditions of the uterus, such as endometriosis, infections or polyps, may lead to heavy periods. Cancer of the lining of the uterus (endometrial cancer) is a very rare cause. Most cases of endometrial cancer develop in women aged in their 50s or 60s.
  • Hormonal problems. Periods can be irregular and sometimes heavy if you do not ovulate every month. For example, this occurs in some women with polycystic ovary syndrome. Women with an underactive thyroid gland may have heavy periods.
  • The intrauterine contraceptive device (IUCD, or coil) sometimes causes heavy periods. However, a special hormone-releasing IUCD called the intrauterine system (IUS) can actually treat heavy periods .
  • Pelvic infections. There are different infections that can sometimes lead to heavy bleeding developing. For example, chlamydia can occasionally cause heavy bleeding. These infections can easily be treated with antibiotics.
  • Warfarin or similar medicines interfere with blood clotting. If you take one of these medicines for other conditions, it may have a side-effect of heavier periods.
  • Some drugs used for chemotherapy can also cause heavy periods.
  • Blood clotting disorders are rare causes of heavy bleeding. Other symptoms are also likely to develop, such as easy bruising or bleeding from other parts of the body.
  • If you stop taking the contraceptive pill it may appear to cause heavy periods. Some women become used to the light monthly bleeds that occur whilst on the pill. Normal periods return if you stop the pill. These may appear heavier, but are usually normal.

Are any tests required for heavy periods?

A doctor may want to do an internal (vaginal) examination to examine your cervix (neck of the womb) and also to assess the size and shape of your uterus. However, an examination is not always necessary, especially in younger women who do not have any symptoms to suggest anything other than dysfunctional uterine bleeding.
A blood test to check for anaemia is usually performed.

If you bleed heavily each month then you may not take in enough iron in your diet, needed to replace the blood that you lose. (Iron is needed to make blood cells.) This can lead to anaemia which can cause tiredness and other symptoms. Up to 2 in 3 women with recurring heavy periods develop anaemia.
If the vaginal examination is normal (as it is in most cases), and you are under the age of 40, no further tests are usually needed. The diagnosis is usually dysfunctional uterine bleeding and treatment may be started if required. Further tests may be advised for some women, especially if there is concern that there may be a cause for the heavy periods other than dysfunctional uterine bleeding. For example:

  • Women over the age of 40 who develop heavy periods.
  • If treatment for presumed dysfunctional uterine bleeding does not seem to help.
  • Any woman where a doctor detects a large or abnormal uterus, or who has other symptoms which may indicate an underlying problem. For example, if you:
  • Bleed between periods, or have irregular bleeding.
  • Have bleeding or pain during, or just after, sex.
  • Have pain apart from normal period pains.
  • Have any change in your usual pattern of bleeding, particularly if you are over the age of 40.
  • Have symptoms suggesting a hormonal problem or blood disorder.

If tests are advised then they may include one or more of the following:

  • An ultrasound scan of your uterus.
  • Internal swabs. This may be done if an infection is the suspected cause of the heavy bleeding.
  • Endometrial sampling. This is where a thin tube is passed into the uterus. Gentle suction is used to obtain small samples (biopsies) of the uterine lining (endometrium). This is usually done without an anaesthetic. This is more likely to be done if you are aged over 45 years, have persistent bleeding or have tried treatment without it helping. The samples are looked at under the microscope for abnormalities.
  • Hysteroscopy. This is where a doctor can look inside the uterus. A thin telescope is passed into your uterus through your cervix via the vagina. This too can often be done without an anaesthetic. Small samples can also be taken during this test.
  • Blood tests. For example, if an underactive thyroid gland or a bleeding disorder is suspected.

Keeping a menstrual diary.

It may be worth keeping a diary for a few periods (before and after any treatment). Your doctor may give you a chart which you can fill in. Basically, you record the number of sanitary towels or tampons that you need each day, and the number of days of bleeding.

How is heavy periods treated?

Treatment aims to reduce the amount of blood loss.

Not treating

This is an option if your periods do not interfere too much with normal life. You may be reassured that there is no serious cause for your heavy periods, and you may be able to live with them. A blood test may be advised every so often to check for anaemia. Iron tablets can correct anaemia.

Levonorgestrel intrauterine system (LNG-IUS)

This treatment usually works very well. The LNG-IUS is similar to an intrauterine contraceptive device (IUCD, or coil). It is inserted into the uterus and slowly releases a small amount of a progestogen hormone called levonorgestrel. The amount of hormone released each day is tiny but sufficient to work inside the uterus. In most women, bleeding becomes either very light or stops altogether within 3-6 months of starting this treatment. Period pain is usually reduced too. However, the light periods may become irregular. The LNG-IUS works mainly by making the lining of the uterus very thin.

The LNG-IUS is a long-acting treatment. Each device lasts five years, although it can be taken out at any time. It is particularly useful for women who require long-term contraception, as it is also a reliable form of contraception. See separate leaflet called 'Intrauterine System' for details. This is, however, not usually suitable if you do not need long-term (for at least one year) contraception.

Tranexamic acid tablets

Tranexamic acid tablets are an option if the LNG-IUS is not suitable or not wanted. Treatment with tranexamic acid can reduce the heaviness of bleeding by almost half (40-50%) in most cases. However, the number of days of bleeding during a period is not reduced, and neither is period pain. You need to take a tablet 3-4 times a day, for 3-5 days during each period. Tranexamic acid works by reducing the breakdown of blood clots in the uterus. In effect, it strengthens the blood clots in the uterus lining which leads to less bleeding. If side-effects occur they are usually minor, but may include an upset stomach.

Anti-inflammatory painkillers

There are various types and brands. Most are available only on prescription but you can buy one called ibuprofen from pharmacies. Your doctor may prescribe ones called mefenamic acid or naproxen. These medicines reduce the blood loss by about a third (20-50%) in most cases. They also ease period pain. You need to take the tablets for a few days during each period. They work by reducing the high level of prostaglandin in the uterus lining which seems to contribute to heavy periods and period pain. However, they do not reduce the number of days the period lasts.

The combined oral contraceptive pill (COCP)

This reduces bleeding by at least a third in most women. It often helps with period pain too. It is a popular treatment with women who also want contraception, but who do not want to use the LNG-IUS. If required, you can take this in addition to anti-inflammatory painkillers (described above), particularly if period pain is a problem.

Long-acting progestogen contraceptives

The contraceptive injection and the contraceptive implant also tend to reduce heavy periods. For example, up to half of women on the contraceptive injection have no periods after a year. They are not given as a treatment just for heavy periods. However, if you require contraception then one of these may be an option for you.


Norethisterone is a progestogen medicine. It is not commonly used to treat heavy periods. It is sometimes considered if other treatments have not worked, are unsuitable or are not wanted. Norethisterone is given to take on days 5-26 of your menstrual cycle (day one is the first day of your period). However, taking norethisterone in this way does not act as a contraceptive.

The reason why norethisterone is not commonly used as a regular treatment is because many women get side-effects, such as bloating, fluid retention, breast tenderness, nausea, headache and dizziness.

Other medicines

Other hormone treatments, such as gonadotrophin-releasing hormone (GnRH) analogues, are occasionally used by specialists in hospital. However, they are not routine treatments due to various side-effects that commonly occur.

Surgical treatment

Having surgery is not a first-line treatment. It is an option if the above treatments do not help or are unsuitable:

Removing or destroying the lining of the uterus is an option. This is called endometrial ablation or resection. An instrument is passed into the uterus via the vagina. The aim is to remove as much of the uterus lining as possible. This can be done by various ways such as by using heat, microwaves, and cryotherapy. This treatment prevents women from having children in the future.

Hysterectomy is the traditional operation where the uterus is totally removed. However, hysterectomy is done much less commonly these days since endometrial ablation became available in the 1990s. It may be considered if all other treatment options have not worked for you.

Emergency treatment to rapidly stop heavy bleeding

Some women have very heavy bleeding during a period. This can cause a lot of blood loss, and distress. One option as an emergency treatment is to take a course of norethisterone tablets. Norethisterone is a progestogen medicine.

Progestogens act like the body's natural progesterone hormones - they control the build-up of cells lining the womb.

So, if a period is very heavy or prolonged, your doctor may advise that you take norethisterone tablets. A dose of 5 mg three times daily for 10 days is the usual treatment. Bleeding usually stops within 24-48 hours of starting treatment. If bleeding is exceptionally heavy then 10 mg three times daily may be given. This should then be tapered down to 5 mg three times daily for a week, once your bleeding has stopped.

A note for teenagers with heavy periods

Heavy periods due to dysfunctional uterine bleeding seem to be more common in the first few years after starting periods (and in the months running up to the menopause). If you are a teenager and have heavy periods, you have a good chance that they will settle down over a few years and become less heavy.


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