The normal menstrual cycle lasts about 28 days and it can be shorter or longer by about 7 days.  Each cycle starts with the first day of bleeding of one period and ends with the first day of the next.

When menstrual cycles are longer than 35 days or shorter than 21 days, it becomes abnormal.  When menstruation does not occur for 3 to 6 months, this is called amenorrhea, and should be of concern.

Abnormal uterine bleeding (AUB) is irregular bleeding from the uterus that is longer or heavier than usual or does not occur at your regular time.  Bleeding in any of the following situation is abnormal:

  • Bleeding between periods
  • Bleeding after sex
  • Spotting anytime in the menstrual cycle
  • Bleeding heavier or for more days than usual
  • Bleeding after menopause

AUB occurs in any age, but there is a certain time of a woman’s life that their menses are irregular.  For example, menses in a girl, a few years after her first menses (menarche), may not occur on schedule.  Also, cycle length may change when women is nearing menopause.

Abnormal uterine bleeding has many causes. It is sometimes caused by changes in hormone levels. It can also be caused by problems such as growths in the uterus or clotting problems.

In some cases the cause of the bleeding isn’t known, then it is known as a dysfunctional uterine bleeding (DUB).  This reflects a disruption in the hormones.

Abnormal uterine bleeding can either be:

  • Anovulatory, which occurs when periods are irregular with absent, minimal or excessive bleeding. Under this type are the women who never had their menses and those who have infrequent periods.
  • Ovulatory, this occurs in periods that occur regularly but have excessive bleeding or lasts longer than 7 days.

Symptoms of abnormal uterine bleeding include:

  • Vaginal bleeding that occurs more often than every 21 days or farther apart than 35 days (a normal teen menstrual cycle can last up to 45 days).
  • Vaginal bleeding that lasts longer than 7 days (normally lasts 4 to 6 days).
  • Blood loss of more than 80 mL (3 fl oz) each menstrual cycle [normally about 30 mL (1 fl oz)]. If you are passing blood clots and soaking through your usual pads or tampons each hour for 2 or more hours, your bleeding is considered severe.

Your doctor looks for a number of possible causes of your bleeding.

First tests

First, your doctor will:

  • Review your history of symptoms and menstrual periods. (If possible, bring with you a record of the days you had your period, how heavy or light the flow was, and how you felt each day.)
  • Conduct a routine pelvic exam.
  • Find out whether you are ovulating regularly.

Other tests

If your symptoms are severe, your doctor suspects a serious medical problem, or you are considering a certain treatment, you may also have one or more other tests, such as:

  • Blood tests, which may include:
    • Pregnancy test (human chorionic gonadotropin, or hCG).
    • Complete blood count (CBC), to check for signs of disease, infection, and anemia.
    • Thyroid-stimulating hormone (TSH) to check for a thyroid gland problem, which can cause menstrual irregularity.
    • Serum prolactin level, to check for a pituitary gland problem, which can interfere with or stop the menstrual cycle.
    • Serum ferritin, to check for anemia, a symptom of heavy blood loss.
  • Pap smear and cultures to check for infection or abnormal cervical cells.
  • Urine test to screen for infection, disease, and other signs of poor health.
  • Transvaginal pelvic ultrasound, to check for any abnormalities in the pelvic area. After the pelvic exam, a transvaginal ultrasound is often the next step in diagnosing a vaginal bleeding problem. If a pelvic mass is found, ultrasound results are useful for making further testing and treatment decisions.
  • Sonohysterogram, which uses ultrasound to monitor the movement of a salt solution (saline), which is injected into the uterus. This test may be done to look for uterine polyps or fibroids.
  • Endometrial biopsy, usually for women older than 35 or who are postmenopausal, to learn whether the lining of the uterus (endometrium) is healthy and functioning normally.
  • Hysteroscopy, if no cause is apparent but a problem condition is suspected; to check for and treat a suspected condition, such as uterine fibroids; or if bleeding continues despite treatment.



Hormonal medications are often used to control abnormal uterine bleeding.  The type of hormone you will take depend on whether you want to get pregnant as well as your age.

Medicine choices

There are several hormone therapies for managing abnormal uterine bleeding. These treatments help reduce bleeding and regulate the menstrual cycle:

  • Birth control pills (synthetic estrogen and progesterone). This can reduce the amount of heavy menstrual bleeding by about half. This can also make the cycle more regular.
  • Progestin pills (synthetic progesterone). In some women, progestins can control endometrial growth and bleeding. You usually take progestins 10 to 12 days every month.
  • The levonorgestrel intrauterine device (IUD). A doctor inserts this birth control device into your uterus through your vagina. It stays in your body for up to 5 years and releases levonorgestrel, a form of progesterone, into the uterus.
  • Estrogen. In some severe or urgent cases, estrogen may be used to reduce bleeding.
  • Hormone suppressors such as gonadotropin-releasing hormone analogues (GnRH-As). GnRH-As are rarely used. These drugs reduce estrogen production, making your body think it is in menopause. This reduces or stops menstrual periods for as long as you take the medicine. Side effects with GnRH-As are common.
  • Nonsteroidal antiinflammatory drugs (NSAIDs) decreases bleeding and is used together with oral contraceptives.

A medicine called tranexamic acid (such as Lysteda) is sometimes used for women who have bleeding that is heavier than normal. This medicine is not a hormone. It prevents bleeding by helping blood to clot. Talk to your doctor to find out if this option is right for you.

Related Articles


Overview and FactsTypes and SymptomsDiagnosis & MedicationsOverview and Facts Referred pain is a phenomenon where pain is perceived at a [...]


Overview and FactsTypes and SymptomsDiagnosis & MedicationsOverview and Facts Quinoline yellow is a synthetic food colorant commonly used in the [...]


Overview and FactsTypes and SymptomsDiagnosis & MedicationsOverview and Facts Pneumothorax is a condition characterized by the presence of air in [...]