From the Guidelines
The workup for abnormal uterine bleeding should begin with a thorough history and physical examination, followed by initial laboratory tests including a pregnancy test, complete blood count, thyroid function tests, and coagulation studies, and transvaginal ultrasound as the first-line imaging study to evaluate the endometrium and identify structural abnormalities. The evaluation of abnormal uterine bleeding (AUB) is crucial to identify potential causes, which can range from hormonal imbalances to structural abnormalities and malignancy 1.
Initial Evaluation
The initial evaluation should include:
- A thorough history to identify potential causes of AUB
- Physical examination to assess for signs of bleeding or other abnormalities
- Laboratory tests, including:
- Pregnancy test to rule out pregnancy as a cause of bleeding
- Complete blood count to assess for anemia or other blood disorders
- Thyroid function tests to evaluate for thyroid dysfunction
- Coagulation studies to assess for bleeding disorders
Imaging Studies
Transvaginal ultrasound is the recommended first-line imaging study to evaluate the endometrium and identify structural abnormalities such as fibroids, polyps, or endometrial thickening 1. If structural abnormalities are suspected but not clearly visualized on ultrasound, saline infusion sonohysterography or hysteroscopy may be performed for better visualization.
Endometrial Sampling
For women over 35 or those with risk factors for endometrial cancer, endometrial sampling (biopsy) is recommended to rule out malignancy, which can be performed in the office using an endometrial pipelle 1. Hysteroscopy allows direct visualization of the uterine cavity and targeted biopsy of suspicious lesions.
Additional Testing
Additional testing may include assessment of ovulatory function through serum progesterone levels during the luteal phase or evaluation for polycystic ovary syndrome with androgen levels. The workup should be tailored to the patient's age, risk factors, and clinical presentation, as the differential diagnosis varies widely from hormonal imbalances and structural abnormalities to systemic conditions and malignancy.
From the Research
Workup for Abnormal Uterine Bleeding
The workup for abnormal uterine bleeding involves a comprehensive approach to determine the underlying cause of the bleeding. The following steps are involved in the workup:
- A detailed history and physical examination, including a pelvic examination, to identify any potential causes of the bleeding 2, 3, 4, 5, 6
- Laboratory testing, including a pregnancy test and complete blood count (CBC) with platelets, to rule out any underlying medical conditions 2, 4, 5
- Endometrial sampling, which should be performed in patients 45 years and older, and in younger patients with a significant history of unopposed estrogen exposure 2
- Transvaginal ultrasonography, which is the preferred imaging modality, to evaluate for any structural causes of the bleeding, such as polyps, adenomyosis, or leiomyomas 2, 4
Classification of Abnormal Uterine Bleeding
Abnormal uterine bleeding can be classified using the PALM-COEIN system, which categorizes the causes of bleeding into:
- PALM: structural etiologies, including polyp, adenomyosis, leiomyoma, malignancy, and hyperplasia 2, 3, 5, 6
- COEIN: nonstructural etiologies, including coagulopathy, ovulatory dysfunction, endometrial disorders, iatrogenic causes, and not yet classified causes 2, 3, 5, 6
Diagnostic Tests and Procedures
The following diagnostic tests and procedures may be used to evaluate abnormal uterine bleeding:
- Endometrial biopsy to rule out endometrial cancer or hyperplasia 4
- Dilatation and curettage (D&C) to evaluate for any intrauterine abnormalities 4
- Hysteroscopy to visualize the inside of the uterus and diagnose any structural causes of bleeding 4
- Transvaginal ultrasonography to evaluate for any structural causes of bleeding, such as polyps or leiomyomas 2, 4