Abnormal Uterine Bleeding
Dipa Joshi
Roxanne Marie Jamshidi
The evaluation of abnormal uterine bleeding (AUB) requires characterization and quantification of the bleeding, specifically the onset, duration, frequency, amount, pattern, and associated symptoms.
MENSTRUAL DIMENSIONS
The mean menstrual blood loss in women with normal hemoglobin and iron levels is 35 mL, with 95% of women losing <60 mL each menstrual cycle.
Menstrual frequency may be characterized as:
Normal—21 to 35 days
Oligomenorrhea—menstrual intervals longer than 35 days
Polymenorrhea—menstrual intervals shorter than 21 days
The volume of menstrual blood loss and cycle regularity should be determined, although this can be based on subjective patient report.
Normal blood loss—5 to 80 mL
Regular cycles—2 to 20 days cycle-to-cycle variation over 12 months
Light cycle—<5-mL blood loss
Menorrhagia—heavy, regular periods with >80-mL blood loss
Metrorrhagia—irregular bleeding, especially between cycles
Menometrorrhagia—heavy, irregular bleeding that includes intermenstrual bleeding
Withdrawal bleeding—a predictable pattern of bleeding that occurs after the withdrawal of progestin therapy
Breakthrough bleeding—unpredictable bleeding that occurs while on hormonal contraception
Duration of menstrual bleeding is defined as:
Normal—4 to 6 days
Prolonged—>7 days
Shortened—<3 days
Dysmenorrhea: pain associated with menstruation that can interfere with daily activities
DIFFERENTIAL DIAGNOSIS OF ABNORMAL UTERINE BLEEDING
Causes of uterine bleeding can be organized by age groups (Table 40-1).
Prepubertal Abnormal Uterine Bleeding
Benign prepubertal bleeding may occur in the first few days of life due to the withdrawal of maternal estrogen, but all other cases of bleeding require evaluation.
See Chapter 34.
Reproductive Age Abnormal Uterine Bleeding
AUB in the reproductive years is associated with pregnancy, anovulatory bleeding, structural causes, and coagulation disorders.
History and Physical Exam
The patient’s sexual history, past medical history, gynecologic and obstetric history, and contraceptive and medication regimens are pertinent. Any change in the patient’s diet, weight, and exercise pattern is relevant.
Family history should be reviewed for possible bleeding disorders.
Adolescent girls should be screened for physical abuse.
Notable physical exam findings include weight, evidence of hyperandrogenism (e.g., hirsutism, acne), thyroid nodules, evidence of insulin resistance (e.g., acanthosis nigricans), and evidence of bleeding disorders (e.g., petechiae, ecchymoses, skin pallor).
Inspection of the vaginal vault may reveal discharge suggestive of infection or evidence of trauma, lesions, polyps, products of conception, or masses.
A bimanual examination should be performed to evaluate the internal os; presence of cervical motion tenderness; size and contour of uterus and adnexa; and presence of any palpable masses, lesions, or tenderness.
Tanner staging should be documented (see Chapter 34).
TABLE 40-1 Differential Diagnosis of Abnormal Uterine Bleeding by Age Group | |||||||||||||||
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Diagnostic Testing
Order laboratory urine (or serum) human chorionic gonadotropin (β-hCG) to assess for pregnancy, thyroid-stimulating hormone (TSH), prolactin, and complete blood count.
In patients with history or physical exam suggesting genital tract infection, cervical or vaginal swabs to assess for sexually transmitted infections such as chlamydia, gonorrhea, herpes, or trichomonas can be of use.
In women with risk factors for neoplastic processes, a tissue diagnosis is required (i.e., endometrial biopsy).
In women at risk for coagulopathy, targeted screening of bleeding disorders is recommended (discussed later in this chapter).
Imaging can be ordered to look for an anatomic cause of bleeding (e.g. fibroid, endometrial polyp).
Perimenopause Abnormal Uterine Bleeding
Perimenopausal AUB is most commonly due to anovulation and structural abnormalities (e.g., fibroids, polyps), however may be attributed to hyperplasia or malignancy.
History, Exam, and Testing
In addition to routine history obtained for women of other ages, menopausal symptoms (e.g., vasomotor symptoms, sleep disturbances, mood disturbances) should be explored.
Order TSH, follicle-stimulating hormone, and prolactin.
Imaging should evaluate for fibroids. See Chapter 37.
Obtain tissue specimens/biopsies (e.g., cervical, endometrial) if indicated.
Infectious workup is recommended in patients at risk.
Postmenopause Abnormal Uterine Bleeding
Postmenopausal AUB is primarily caused by endometrial and vaginal atrophy. However, as approximately 15% of these women will have some form of hyperplasia and 7% to 10% will have endometrial cancer, AUB in the age group suggests malignancy until proven otherwise.
As with very young patients, careful attention should be paid to determine the source of bleeding, such as the rectum.
Tissue sampling and imaging in this population are essential.
Infectious workup is recommended in patients at risk.
EVALUATION OF ABNORMAL UTERINE BLEEDING
Ultrasonography
Transvaginal ultrasonography (TVUS) is useful to evaluate for the presence of fibroids, polyps, intrauterine pregnancy, and ectopic pregnancy. In the workup for possible malignant processes, sonography can be used to search for a thickened endometrium and masses within the uterus, adnexa, or cervix.
TVUS is a better diagnostic tool in postmenopausal than premenopausal women, with a sensitivity of 94% and specificity of 78% in diagnosing an endometrial abnormality in this population using a cutoff of 5 mm for the endometrial echo.
On the other hand, for reproductive age women, as useful as TVUS is at assessing the myometrium, it is only 56% sensitive and 73% specific for assessment of the intrauterine cavity.
Saline infusion sonography, or sonohysterography, involves distention of the uterine cavity with sterile saline to enhance visualization of the endometrial surface during TVUS. Sonohysterography is the most sensitive noninvasive method of diagnosis for endometrial polyps and submucous myomata. However, it does not distinguish between benign and malignant processes.
Hysteroscopy
The gold standard for evaluating the endometrial cavity is hysteroscopy. The advantage of this procedure is that it provides direct visualization of the endometrial cavity and can be performed in the office setting or operating room. It can be both diagnostic and operative, allowing for directed biopsies and excision of polyps and small myomas. Office hysteroscopy with targeted biopsies has a sensitivity and specificity of 98% and 95%, respectively, compared with histologic findings at the time of hysterectomy.
Magnetic Resonance Imaging
Pelvic magnetic resonance imaging (MRI) can be useful in the diagnosis of adenomyosis and can accurately localize and measure fibroids, facilitating determination of the best treatment (e.g., embolization, resection, hysterectomy).
Endometrial Sampling
The American College of Obstetricians and Gynecologists (ACOG) recommends endometrial sampling in women older than age 45 years as a first-line test. Women younger than 45 years with risk factors for unopposed estrogen (e.g., obesity, polycystic ovarian syndrome), those who have failed medical management or have persistent AUB, are also recommended by ACOG to undergo endometrial sampling.
Endometrial sampling is a rapid, safe, and cost-effective procedure that can be performed in the office to evaluate AUB. A potential drawback is that the biopsy does not sample the entire endometrium and a localized lesion may be missed: The posttest probability of endometrial cancer from an office endometrial biopsy is approximately 80% for a positive test result and 1% for a negative test result.
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