A 38-year-old nulligravid woman comes to the office due to persistent abnormal uterine bleeding. The patient's menstrual periods previously occurred monthly and consisted of 4 days of moderate bleeding and light cramping. However, for the past 8 months, she has had intermenstrual spotting and bleeding that have occurred at varying intervals and last 3-7 days. She was started on combination oral contraceptives 4 months ago, which has not improved the bleeding pattern. Temperature is 37.2 C (99 F), blood pressure is 126/76 mm Hg, and pulse is 86/min. BMI is 29 kg/m2. Speculum examination shows dark red blood in the posterior vaginal vault but no cervical or vaginal lesions. The remainder of the pelvic examination is normal. Laboratory results are as follows:
| Hemoglobin | 12.2 g/dL |
| Prolactin | 5 ng/mL |
| TSH | 1.8 µU/mL |
Urine pregnancy test is negative. Pelvic ultrasound shows an anteverted uterus and no adnexal masses. Which of the following is the best next step in the management of this patient?
Show Explanatory Sources
This patient's intermenstrual bleeding and irregular menses are consistent with abnormal uterine bleeding (AUB), which is commonly due to uncontrolled endometrial proliferation (from unregulated excess estrogen) and is associated with an increased risk of endometrial hyperplasia/cancer.
In women age <45 with AUB (such as this patient), the absolute risk of endometrial hyperplasia/cancer is low; therefore, they can be started on combination estrogen/progestin contraception (ie, medical management) without evaluation of the endometrium. The estrogen component regulates the menstrual cycle and builds up the endometrium; the progestin component sheds the endometrium.
However, patients such as this one who have continued irregular menstrual bleeding while on combination contraceptives (ie, failed medical management) require further evaluation. In such patients, the endometrial lining is likely too thick for the progestin to completely shed the endometrium during menstruation; as a result, the unshed endometrium continues to undergo dysregulated proliferation, which leads to an increased risk of endometrial hyperplasia/cancer. Therefore, patients age <45 with AUB who have failed medical management require an endometrial biopsy.
Other indications for endometrial biopsy in women age <45 include persistent (>6 months) AUB, obesity, or tamoxifen therapy, all of which increase the amount of unopposed endometrial estrogen exposure.
(Choice A) Coagulation studies can be performed in patients with heavy menstrual bleeding and anemia to evaluate for bleeding disorders (eg, von Willebrand disease). This patient has a normal hemoglobin.
(Choice B) Patients with heavy, regular (ovulatory) bleeding can be treated with an endometrial ablation, a procedure that destroys the endometrium. Undiagnosed AUB is a contraindication to endometrial ablation because it can prevent evaluation of the endometrium in patients with possible endometrial hyperplasia/cancer.
(Choice D) A hysterosalpingogram is used to evaluate for abnormalities of the uterus (eg, didelphys) or of the Fallopian tube (eg, scarring). It is not used in evaluation of AUB. In addition, undiagnosed AUB is a relative contraindication to a hysterosalpingogram because the procedure could spread cancerous endometrial cells into the abdomen.
(Choice E) A progesterone withdrawal test is used to evaluate secondary amenorrhea (no menses >6 months in patients with previously irregular menses) to determine if the amenorrhea is from low estrogen levels (ie, no bleeding after progesterone). This patient has continued bleeding while on oral contraceptives (suggesting high estrogen levels); therefore, this test is not indicated.
Educational objective:
Women age <45 with abnormal uterine bleeding who have failed medical management (eg, oral contraceptives) require evaluation for endometrial hyperplasia/cancer with an endometrial biopsy.