Abnormal (or dysfunctional) uterine bleeding is vaginal bleeding that is abnormally frequent, infrequent, heavy, or light. Every year, more than a million women complain of heavy or irregular periods. The terms are relative, but heavy bleeding is classified as a 50% increase in normal flow, or soaking through more than 10 tampons or sanitary pads in a day. Bleeding that lasts longer than a week is also considered to be heavy. Getting a short or light period every two to three weeks instead of one monthly period is considered to be irregular, as is spotting or missing periods altogether.
Half of abnormal uterine bleeding cases occur during the childbearing years. Pregnancy is the most common cause of missed periods. The hormonal changes that occur during the years leading up to menopause (known as perimenopause) are another common cause of skipped periods and menstrual irregularities.
Abnormal uterine bleeding can be broken into two categories: 1) problems that are hormonal in origin; and 2) those that are organic in origin—most commonly fibroid tumors, uterine polyps, or a systemic disease such as cancer or a blood-clotting disorder.
Hormonal imbalances that interfere with ovulation can result in abnormal uterine bleeding. A number of things can interfere with the intricate hormonal balance that affects ovulation and bleeding.
- Pregnancy. In women of childbearing age, pregnancy is the leading cause of skipped periods.
- Perimenopause. The hormonal changes that occur during the years leading up to menopause (the cessation of menstruation) can cause bleeding abnormalities.
- Stress. Stress hormones such as cortisol are known to interfere with ovulation.
- Polycystic ovary syndrome (PCOS). PCOS is a condition in which the ovaries become filled with tiny cysts and enlarge. The problem occurs when the pituitary gland produces too much of a hormone called luteinizing hormone (LH). The hormonal imbalance that results creates an overabundance of uterine lining that makes bleeding irregular.
- Other hormonal causes. Problems that originate in the thyroid gland, pituitary gland, or adrenal glands can disrupt ovulation.
A physical problem in the uterus can cause abnormal bleeding.
- Fibroids. Fibroids are noncancerous growths that invade the wall of the uterus in at least 20% of women over the age of 35. Fibroids may appear singly or in clusters, and be as small as a grape or as big as an orange. They are comprised of muscle and fibrous tissue, and may cause excessive flow during menstruation or bleeding between periods.
- Polyps. Polyps are another type of noncancerous growth that can invade the cervix or uterus. Polyps may be so small that they go unnoticed, or may be big enough to poke into the uterine or pelvic cavity and cause abnormal bleeding.
- Pelvic inflammatory disease (PID). PID is a condition in which the fallopian tubes become inflamed, usually due to a sexually acquired infection. Irregular bleeding is one of the many symptoms of PID.
- Uterine cancer. Uterine cancer is a malignant growth in the uterus. It can occur in the lining of the uterus (endometrium) or in its muscular walls (uterine sarcoma). Endometrial cancer is the most common cancer of the female reproductive system, and almost always strikes postmenopausal women between ages 50 and 70. Any vaginal bleeding that occurs after menopause should be checked out right away.
Abnormal uterine bleeding can be a consequence of another medical problem.
- Blood-clotting disorders. Problems with blood clotting can trigger abnormal uterine bleeding. A coagulation disorder called Von Willebrand’s disease is one culprit, affecting about 1% of the population.
- Eating disorders. Women with very low body fat due to an eating disorder, strict dieting, or excessive exercise frequently can cease to ovulate and menstruate.
Uterine growths sometimes produce a heavy menstrual flow or spotting between periods. PCOS makes periods absent or irregular. Post menopausal vaginal bleeding may be a sign of uterine cancer.
- Heavy bleeding. Heavy bleeding is classified as a 50% increase in normal flow or soaking through more than 10 tampons or sanitary pads in a day. Bleeding that lasts longer than a week is also considered heavy.
- Spotting. Episodes of breakthrough bleeding that occur between regular menstrual periods is called spotting.
- Absent periods. Periods may stop once they have started (called secondary amenorrhea), or they may never begin in the first place (called primary amenorrhea).
- Irregular periods. Getting a short or light period every two to three weeks instead of one monthly period is considered to be irregular. Bleeding after menopause, as well, is irregular and should be investigated right away.
Pregnancy and obesity can contribute to fibroid development, leading to abnormal uterine bleeding.
Fibroids are a major cause of abnormal uterine bleeding in women over the age of 30. One-third of women over the age of 30 have fibroids. Doctors do not know why some women develop fibroids, but these benign tumors appear to be fed by estrogen. Fibroids typically grow during pregnancy, when estrogen levels are high, and shrink after menopause when estrogen levels are low. Obesity also contributes to fibroid development, perhaps because fat cells produce estrogen.
Having a family member with polycystic ovary syndrome puts you at risk for the condition, and thus at risk for abnormal uterine bleeding. Polycystic ovary syndrome (PCOS) affects between 5% and 10% of women during their reproductive years. The cause of PCOS is unknown, but it seems to run in families. Symptoms often occur during puberty right around the time that periods normally start. Weight gain, acne, and male-pattern body hair are other symptoms of PCOS. If left untreated, the condition can result in infertility and lead to uterine cancer later in life.
Obesity, hypertension, diabetes, PCOS, and late menopause are all associated with an increased risk of uterine cancer, and therefore abnormal uterine bleeding. Uterine cancer usually strikes women after menopause.
The disease also occurs with higher frequency in postmenopausal women who have used unopposed estrogen therapy on a long-term basis. It occurs with less frequency in those who have used oral contraceptives. The cancer tends to be more common in women who have had few or no children.
The first thing your doctor will do is take a thorough medical history to determine the cause of your abnormal bleeding. Your doctor will ask you about the characteristics of your bleeding in terms of heaviness, duration, and frequency, as well as other symptoms you might have. For example, do you also experience cramps, bloating, and mood swings? Does bleeding occur after exercise, a bowel movement, or sex? If certain activities make bleeding worse, the cause might be a physical problem such as polyps or fibroids. Painless, unpredictable bleeding is likely to stem from a hormonal problem that affects ovulation, whereas multiple symptoms suggest that ovulation is still taking place and that the problem is physical. Your doctor will ask about your sexual history, any gynecological diseases you may have had, your use of medications and oral contraceptives, and other known medical problems.
The next step is a physical examination. Your doctor will examine you for evidence of thyroid problems, liver disease, blood-clotting disorders, eating disorders, and other conditions that are known to cause abnormal uterine bleeding. He or she will also do an internal pelvic exam to look for vaginal erosions, uterine polyps, and fibroids. Some growths may be big enough to feel.
Diagnostic tests may be needed. A pap smear can indicate cervical abnormalities that warrant further investigation. A pregnancy test and a complete blood cell count are an important part of the diagnostic work-up. Your doctor may also wish to take blood samples to test for possible clotting disorders and other problems.
Your doctor may suggest an ultrasound. Abdominal and vaginal ultrasounds can reveal polyps, fibroids, and other types of tumors. Your doctor may wish to do a sonohysterogram, which involves inserting a small amount of sterile saline into the endometrial cavity and then doing a vaginal ultrasound. This provides a very clear picture.
If you are over the age of 35 or have other risk factors for uterine cancer (PCOS, obesity, having had few or no children), your doctor may order an endometrial biopsy. During this simple, nearly painless procedure, your doctor will take tissue samples from your uterine lining using a small, flexible device.
Your doctor may wish to perform dilation and curettage (D&C) with hysteroscopy. During this procedure, your doctor will use a fiber optic tube called a hysteroscope to examine your uterus and scrape away tissue from the uterine lining.
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