The menstrual cycle is not the same for every woman. On average, menstrual flow occurs every 28 days (with most women having cycles between 24 and 34 days), and lasts about 4 days. However, there is wide variation in timing and duration that is still considered normal, especially if your periods began within the last few years.

If you completely soak through a sanitary pad or tampon every hour for 2-3 consecutive hours, this is considered a very heavy period. A prolonged period is one that lasts longer than 7 days.

A small percentage of women have periods more often than every 21 days or less often than every 35 days. These variations may be normal.

Bleeding may be something to worry about if it occurs between periods, after intercourse, or if you are over age 50, especially if you have already gone through menopause. The risk of cancer increases with age.

Often, if you are bleeding from the rectum or there is blood in your urine, you may think the blood is coming from the vagina. To know for certain, insert a tampon into the vagina to confirm that it's the source of your bleeding.

• Anovulation (failure of ovaries to produce, mature, or release eggs)
• Endometrial polyps (the endometrium is the inner lining of the uterus)
• Endometrial hyperplasia (thickening/build up of the uterine wall)
• Endometrial cancer
• Uterine fibroids
• Abnormal thyroid or pituitary function
• Pregnancy complications -- like miscarriage or ectopic pregnancy (when a fertilized egg implants somewhere other than the uterus)
• Hormonal changes, such as menopause
• Changes in birth control pills or estrogens that you take
• Use of certain drugs like steroids or blood thinners (for example, warfarin or Coumadin)
• Use of an intrauterine device (IUD) for birth control
• Recent trauma, surgery, or other uterine procedure
• Pelvic inflammatory disease or other infection
• Stress, change in diet or exercise routine, recent weight loss or weight gain, travel, or illness

Keep a record of your menstrual cycles, including when menstruation begins and ends, how much flow you have (count numbers of pads and tampons used, noting whether they are soaked), and any other symptoms you experience. Tampons should be changed at least twice a day to avoid infection.

Because aspirin may prolong bleeding, it should be avoided. Ibuprofen is usually more effective than aspirin for relieving menstrual cramps.

Call your doctor if:

• You have soaked through a pad or tampon every hour for 2-3 hours.
• Your bleeding has lasted longer than one week.
• You are pregnant.
• You have severe pain, especially if you also have pain when not menstruating.
• Your periods have been heavy or prolonged for three or more cycles, compared to what is normal for you.
• You have a fever or abnormal vaginal discharge, especially if it has an odor.
• You have bleeding after menopause.
• You have bleeding or spotting between periods.
• You have nipple discharge, excessive hair growth, deepening voice, unintentional weight loss or gain, or new acne.

Your doctor will perform a physical examination, including a pelvic exam. Your doctor will ask questions like the following to determine the history of this symptom:

• What is your age?
• Have your last three menstrual periods been normal in timing and amount for you?
• How long do your periods usually last?
• How many days are there usually between your menstrual periods?
• How did this cycle (and others) differ from your usual menstruation?
• Have you passed blood clots?
• How many days has the bleeding lasted with these different or abnormal menstrual periods?
• How heavy have they been? How many pads and tampons have you been using per day?
• When was your last menstrual period?
• How old were you when had your first menstrual period?
• Do you use birth control pills? Do you use an IUD for birth control?
• Do you take an estrogen supplement?
• Do you take aspirin more than once per week?
• Do you take Coumadin, heparin, or other anticoagulants?
• Have you recently given birth, had surgery, or experienced trauma on or near the vagina or uterus?
• Have you recently had a vaginal or uterine infection?
• What other symptoms do you have? Abdominal or pelvic pain?
• Do you have nausea or vomiting?
• Are you pregnant or could you be pregnant?
• Have you noticed a growth, lump, or lesion on the genitals?
• Have you had blood in your stools?
• Do you bleed easily?

Diagnostic tests that may be performed include:

• Pap smear
• Endometrial biopsy
• Pelvic ultrasound
• Lab tests such as thyroid function tests, CBC, pregnancy test

Ibuprofen or another prostaglandin inhibitor is often prescribed. Ibuprofen is also available in lower dosages (Advil, Nuprin) without prescription.

In some cases of heavy bleeding, dilation and curettage ("D and C") may be required.

If a tumor is found, surgery (a hysterectomy) will sometimes be needed. Fibroid tumors (uterine fibroids) are common and are not related to cancer.

Fibroids may stop growing by themselves, and surgery may not be needed depending on the amount of bleeding, the location of the fibroid, and the response to various treatment attempts. Fibroids often stop growing at menopause, so an operation can be avoided by waiting. However, if there has been rapid growth of the fibroid tumor or if your Pap smear is abnormal, surgery or another type of therapy may be necessary.

If the heavy bleeding is related to hormonal abnormalities, treatment of the specific abnormality will correct the bleeding. Female hormones (birth control pills or progestins) are commonly used to regulate menses.

Osei J, Critchley H. Menorrhagia, mechanisms and targeted therapies. Curr Opin Obstet Gynecol. 2005; 17(4): 411-418.

James AH. More than menorrhagia: a review of the obstetric and gynaecological manifestations of bleeding disorders. Haemophilia. 2005; 11(4): 295-307.

Warner PE, Critchley HO, Lumsden MA, Campbell-Brown M, Douglas A, Murray GD. Menorrhagia I: measured blood loss, clinical features, and outcome in women with heavy periods: a survey with follow-up data. Am J Obstet Gynecol. 2005; 192(6): 2093-2095.