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Abnormal uterine bleeding in peri- and postmenopausal women

When should you see a clinician about excessive or unexpected bleeding?

Abnormal uterine bleeding (AUB) is a common problem for women of all ages, accounting for up to one-third of gynecologic office visits. The two main types are heavy bleeding that occurs at an appropriate or expected time, such as a heavy menstrual period (menorrhagia), and any type of bleeding that occurs unexpectedly (metrorrhagia). The absence of regular menstrual periods for several months (amenorrhea) is also considered an abnormal bleeding pattern. AUB can be tricky to identify, because what's normal depends on a woman's reproductive age.

In premenopausal women, regular periods are the norm, and most departures from that are likely due to pregnancy, birth control methods, a structural problem (such as fibroids), or a hormone imbalance. During perimenopause (the four to eight years leading up to menopause), irregular bleeding is expected — which makes AUB harder to define and recognize. At this time of life, the distinction between "irregular but normal" perimenopausal periods and "abnormal bleeding" may seem murky, but some guidelines are available (see below). After menopause, bleeding is always a concern and should be investigated, although its significance depends somewhat on whether you're taking hormone therapy.

Perimenopause: What's normal and what's not

During perimenopause, menstrual cycles may become shorter, then longer, and blood flow may vary from month to month. Some women skip periods, and then resume menstruating regularly. The main causes are erratic hormone levels and decreased frequency of ovulations. Fewer ovulations result in hormone changes that cause the endometrium to thicken more than usual before it sloughs off, resulting in heavier, erratic, and prolonged periods.

Although menstrual irregularity is normal during perimenopause, some unusual bleeding can be a sign of a problem that needs medical attention (see "Possible causes of abnormal uterine bleeding in perimenopausal women"). See your clinician if you experience any of the following:

  • very heavy monthly bleeding, especially with clots (for example, soaking through a sanitary product every hour for more than a day)

  • bleeding after sexual intercourse

  • spotting or bleeding between menstrual periods

  • several menstrual cycles that are shorter than 21 days

  • several periods that last three days longer than usual

  • more than three months without a period.

Possible causes of abnormal uterine bleeding in perimenopausal women



Hormonal imbalance*

May cause an absence of periods (amenorrhea). Chronic failure to ovulate can result in an overgrowth of cells lining the uterus, which is a risk factor for abnormal bleeding and for endometrial cancer.


May cause heavy bleeding (menorrhagia). These benign tumors often grow larger during perimenopause and tend to subside after menopause.

Endometrial polyps

May cause heavy, prolonged, or irregular bleeding (often spotting). These benign growths of the uterine lining may or may not need to be removed.


Oral contraceptives may cause various irregular bleeding patterns (skipped pills can cause bleeding between periods). Unmedicated IUDs may increase menstrual flow; hormone-treated IUDs may reduce flow.

Thyroid problems

Hypothyroidism can cause heavy bleeding. Both hypo- and hyperthyroidism are associated with the absence of periods.

Clotting problems

Irregular bleeding may be caused by inherited clotting disorders, such as von Willebrand disease (a rare hereditary bleeding disorder that impairs the blood's ability to clot).


Ectopic pregnancy, miscarriage, placenta previa, and other problem pregnancies can cause irregular bleeding.

Polycystic ovary syndrome

An endocrine disorder characterized by lack of ovulation and few or absent periods. Periods that do occur may be heavy due to abnormal buildup of the uterine lining.

*Possibly due to a change in weight, chronic stress, heavy exercise, illness, perimenopause, or psychotropic medications.

Bleeding in postmenopausal women

A postmenopausal woman may experience a harmless episode of uterine bleeding from a single "rogue ovulation" after more than a year without periods. Also, it's normal for women who take hormone therapy in continuous combined doses of estrogen and a progestogen to experience bleeding or spotting during the first several months — and for women on cyclic hormone regimens to sometimes have light monthly bleeding. But apart from that, bleeding in a postmenopausal woman is abnormal and should be investigated right away. About 10% of postmenopausal women who experience bleeding have endometrial cancer — cancer that arises in the uterine lining, or endometrium. In almost all cases, bleeding is the first sign. (There is no screening test.) If it's discovered and treated early, it's highly curable.

Fortunately, the most common causes of postmenopausal bleeding are far less serious. Usually the problem is age-related thinning (atrophy) of endometrial or vaginal tissues — a benign condition caused by declining estrogen levels. It requires little or no treatment, although vaginal estrogen can help if, for example, the atrophy causes vaginal bleeding after intercourse. Uterine polyps (noncancerous growths in the endometrial lining) are another possible source of bleeding; it may or may not be necessary to remove them. Bleeding may also signal a condition called endometrial hyperplasia — the overgrowth of cells lining the uterus. It's not cancer but in some cases results in the growth of cells that could turn into cancer (atypical hyperplasia). Endometrial hyperplasia is typically treated with medications.

Endometrial cancer risk

Endometrial cancer accounts for about 6% of all cancers in women in the United States. The lifetime risk of the disease is about one in 40; by comparison, lifetime risk of breast cancer is one in eight. Some risk factors for endometrial cancer are

  • age (most cases occur between the ages of 60 and 70)

  • menstruation before age 12

  • late menopause (after age 55)

  • never having given birth, or having a history of infertility

  • obesity (in particular, being 50 pounds overweight)

  • polycystic ovary syndrome

  • endometrial hyperplasia

  • history of taking estrogen without a progestogen

  • history of radiation directed to the pelvis

  • tamoxifen use

  • family history (endometrial cancer in a mother, sister, or daughter, or Lynch syndrome, a rare inherited disorder that increases the risk for several cancers)

Evaluating the endometrium

To diagnose and treat AUB, clinicians must evaluate the endometrium. The goal is, first, to rule out cancer (and precancerous hyperplasia), and then to find out what else might be wrong. Testing for malignancy is important not only in peri- and postmenopausal women but also in women over age 35 with a history of anovulation (not ovulating) or obesity and in women ages 18 to 35 who have risk factors for endometrial cancer (see "Endometrial cancer risk").

Your clinician will take a detailed health history and perform a physical and pelvic exam (including a Pap smear). She or he may order blood tests for pregnancy (in menstruating women), anemia (if excessive bleeding is the problem), abnormal thyroid function, and abnormal hormone levels.

Evaluating the endometrium used to require dilation and curettage (D&C), a surgical procedure usually performed in a hospital under general anesthesia. These days, D&C has largely been replaced by several newer procedures, most of which are performed in an office or outpatient clinic by gynecologic or radiology subspecialists and sonographers. These procedures include the following:

Transvaginal ultrasound. A tampon-sized transducer, or probe, is painlessly inserted into the vagina to generate ultrasound images of the uterus and measure the thickness of the uterine lining. In menstruating women, the technique is most accurate if it's performed immediately after a woman's period, when the endometrium is thinnest. If the endometrium is thickened or difficult to measure, transvaginal ultrasound may be followed by endometrial biopsy (taking a small sample of endometrial tissue), hysteroscopy (visual examination of the uterine lining using a thin, flexible instrument inserted through the cervix), or saline infusion sonography, which improves ultrasound results by filling the uterus with a saltwater solution. According to guidelines issued by the Gynecologic Practice Committee of the American College of Obstetricians and Gynecologists in February 2009, a well-visualized uterus showing an endometrial thickness of 4 millimeters or less rules out endometrial cancer (and the need for biopsy) in postmenopausal women. The situation isn't as clear-cut for premenopausal women, and other techniques should be used for them.

Transvaginal ultrasound images of a normal endometrium and endometrial cancer

Transvaginal ultrasound images of a normal endometrium and endometrial cancer

The image at left shows a normal postmenopausal endometrium (between arrows), which appears as a thin (4 millimeters) uniform line. The image at right shows diffuse endometrial thickening (between arrows) characteristic of endometrial cancer.

Photos courtesy Beryl Benacerraf, M.D.

Transvaginal ultrasound is also helpful in identifying polyps, fibroids, and other anatomical abnormalities.

Endometrial biopsy. A thin tube with a piston-like suction mechanism is inserted into the uterus through the cervix and is used to withdraw samples of uterine cells to check for cancer or precancerous changes. The procedure usually causes cramping, so women are advised to take a nonsteroidal anti-inflammatory drug (ibuprofen, naproxen) beforehand. A local anesthetic near the cervix may also be used. Endometrial biopsy is simple and quick, and partly for that reason has become the most widely used in-office technique for evaluating the endometrium. But since it's performed "blind" (the clinician can't see the endometrium), it may miss polyps or a cancerous lesion that affects only a small part of the uterus. That's why some gynecologists recommend performing transvaginal ultrasound first and following up with biopsy and other techniques.

Hysteroscopy. The entire uterine cavity is directly viewed by means of a fiber-optic tube called a hysteroscope. The hysteroscope is inserted into the uterus through the cervix, and a liquid or gas is introduced to expand the uterus and give the clinician a clear view. Tissue samples can be taken and other procedures, such as polyp or fibroid removal, can be performed (usually under regional or general anesthesia). Hysteroscopy is more expensive, painful, and complicated than transvaginal ultrasound, saline infusion sonography (see below), or endometrial biopsy. However, it's highly accurate in finding and diagnosing cancers, polyps, and other abnormalities, and clinicians have various ways to increase a patient's comfort, such as softening the cervix beforehand with Cytotec (misoprostol).

Saline infusion sonography. This procedure resembles both transvaginal ultrasound and hysteroscopy. To distend the uterus for better visualization, sterile saline is introduced by way of a small catheter through the cervix and into the uterus. An ultrasound probe in the vagina transmits images of the uterus and uterine lining. The clinician can measure endometrial thickness and identify polyps and other abnormalities that don't show up on a standard ultrasound.

Not all of these techniques are available everywhere, and different situations call for different approaches. Consult a clinician who has plenty of experience evaluating AUB. Before your first visit, note down the pattern of your bleeding and any associated symptoms, medications you've taken (including estrogen or a progestogen in any form) and how long you've taken them, your age when you began to menstruate, your age at menopause (if applicable), and any family history of endometrial cancer. Then discuss your options and develop a plan for sorting out the cause of your bleeding. It may take more than one of the above procedures to figure out what's going on.

Date Last Reviewed: 1/1/2011
Date Last Modified: 1/1/2011
Copyright Harvard Health Publications