In a normal menstrual cycle, a woman loses an average of 2 to 3 tablespoons (35 to 40 millilitres) of blood over four to eight days. However, some women have heavy or prolonged menstrual bleeding.


In a normal menstrual cycle, a woman loses an average of 2 to 3 tablespoons (35 to 40 millilitres) of blood over four to eight days. However, some women lose a lot more blood. This is referred to as heavy or prolonged menstrual bleeding, and has also been called menorrhagia. Most women have a menstrual period every 24 to 38 days (that is, the time from the first day of one menstrual period to the onset of the next); the average is every 28 days.

Women who lose 5 to 6 tablespoons (about 80 millilitres) of blood or more during their menstrual period are said to have heavy or prolonged menstrual bleeding. Losing a lot of blood during the menstrual period can cause medical problems such as anaemia (low red blood cell count).




The most common causes of excessive menstrual bleeding are:

  • Not ovulating once per month (called anovulation) – sometimes referred to as ‘Dysfunctional Uterine Bleeding’.
  • Having abnormal tissue in the uterus, such as polyps, fibroids, or adenomyosis.
  • Having a condition that increases bleeding throughout the body.

Anovulation — Anovulation occurs when your ovaries do not produce and release an egg (ovulate) once per month. This causes your menstrual period to be irregular or absent. Anovulation is common in adolescents and in women who are near menopause. Women with polycystic ovary syndrome (PCOS) often do not ovulate regularly.

Abnormal tissue in the uterus — Noncancerous ‘growths’ in the uterus can cause heavy menstrual bleeding. The most common noncancerous ‘growths’ are:

  • Polyps – see section on ENDOMETRIAL POLYPS.
  • Fibroids – see section on UTERINE FIBROIDS.
  • Adenomyosis, in which uterine lining tissue grows into the muscular wall of the uterus.
  • Overgrowth of the lining of the uterus (called endometrial hyperplasia).

Bleeding tendency — Women with certain bleeding conditions or who take certain medicines can have heavy menstrual bleeding.


Women with heavy or prolonged menstrual bleeding typically have one or more of the following:

  • Soak through a pad or tampon every 1 to 3 hours – usually on the heaviest days of the period.
  • Have bleeding for more than seven days.
  • Need to use both pads and tampons at the same time due to heavy bleeding.
  • Need to change pads or tampons during the night.
  • Pass blood clots larger than 2-3cms.
  • Iron deficiency anaemia.

When to seek urgent help — If you soak through 2 pads/tampons in one hour (for two hours in a row), you should see your GP urgently or attend the Accident & Emergency department. Bleeding this heavily can be serious or even life threatening.


If you have heavy menstrual bleeding your doctor will want to perform a clinical assessment, including a pelvic examination. Depending on the history and examination findings, the following tests/investigations may be requested:

  • Blood tests to look for anaemia, thyroid disease, or a bleeding disorder.
  • A pelvic ultrasound scan (usually performed through the vagina).
  • A biopsy of the tissue lining the inside of the uterus, called an endometrial biopsy. This can usually be done in the outpatient setting.
  • A hysteroscopy, which uses a small telescope to look inside the uterus – see section on HYSTEROSCOPY.



The best treatment of heavy menstrual bleeding for you will depend on:

  • The cause of your bleeding
  • Your preferences
  • Whether you need to prevent pregnancy
  • Your desire to have children in the future

Your doctor will probably recommend treatment with one or more medicines first. If these treatments do not reduce bleeding enough, a surgical treatment might be an option.

Hormonal birth control — Hormonal methods of birth control which may be used to treat heavy menstrual bleeding include the pill, skin patch, vaginal ring, injection, implant and hormonal intrauterine system (Mirena IUS). These treatments reduce bleeding during your menstrual period. Hormonal birth control can also reduce cramps and pain during your period. It might take three months for bleeding to improve after you start taking hormonal birth control.

  • Note: All of these hormonal preparations have associated risks/side-effects. Your doctor or nurse will need to discuss these with you prior to commencing treatment.

Antifibrinolytic medicines — Antifibrinolytic medicines can help to slow menstrual bleeding quickly. These medicines work by helping the blood clotting system. A commonly used example is tranexamic acid.

The advantages of antifibrinolytic medicines over other medical treatments are that:

  • The medicine slows bleeding quickly (within two to three hours).
  • You need to take the medicine only a few days each month.
  • The medicine does not contain ‘hormones’ and does not affect your chances of becoming pregnant.

Nonsteroidal anti-inflammatory drugs (NSAIDs) — Nonsteroidal anti-inflammatory drugs, such as Mefenamic acid (Ponstan) can help reduce menstrual bleeding and menstrual cramps. They may be more effective if used in conjunction with an antifibrinolytic agent such as tranexamic acid.

Progestogen pills only — Norethisterone acetate or Medroxyprogesterone acetate in pill form may be used:

  • for part of the cycle (e.g. days 5-26) on a monthly basis or
  • in a higher dose for a short treatment course (usually 10 days) for acute control when bleeding is heavy or prolonged.

Gonadotropin-releasing hormone (GnRH) agonists — GnRH agonists are a type of medicine that can be used to temporarily reduce menstrual bleeding. This treatment might be recommended for women who are waiting to have a surgical treatment.

  • These medicines work by “turning off” the ovaries, causing a temporary menopause. Side effects may include hot flushes and vaginal dryness as might otherwise be experienced by a menopausal woman.

For women who have ‘growths’ in the uterus, such as polyps or fibroids, having a treatment to remove the growth can reduce or end heavy bleeding – see sections on ENDOMETRIAL POLYPS and UTERINE FIBROIDS.

Other surgical treatments for menorrhagia include:

Endometrial ablation — This is a treatment that destroys or removes most of the lining of the uterus. This can reduce heavy menstrual bleeding or cause you to stop having menstrual bleeding. It is not a good option for women who might want to become pregnant in the future and may not be appropriate for women whose abnormal bleeding is caused by anovulation. The cause of the bleeding should be identified before endometrial ablation is performed – see section on ENDOMETRIAL ABLATION.

Hysterectomy — Hysterectomy is a surgery that removes the uterus. This is a permanent treatment that cures heavy menstrual bleeding. However, the surgery has a risk of complications and may require up to six weeks for full recovery. Hysterectomies may be performed laparoscopically (‘key-hole’), vaginally or via laparotomy (larger incision in the abdomen) – see section on HYSTERECTOMY.