What is the workup for abnormal uterine bleeding (AUB)?

From the Guidelines

The workup for abnormal uterine bleeding (AUB) should begin with a thorough history and physical examination, followed by laboratory tests and imaging studies, with combined transabdominal and transvaginal ultrasound of the pelvis with Doppler being the most appropriate initial imaging study, as recommended by the American College of Radiology Appropriateness Criteria 1. The initial evaluation should include a complete blood count, pregnancy test, thyroid function tests, and coagulation studies to rule out underlying medical conditions that may be contributing to the abnormal bleeding.

• The PALM-COEIN classification system can be used to categorize the causes of AUB as structural (polyps, adenomyosis, leiomyomas, malignancy) or non-structural (coagulopathy, ovulatory dysfunction, endometrial, iatrogenic, not otherwise classified) 1.
• For women over 35 or those with risk factors for endometrial cancer, endometrial sampling is recommended, typically via endometrial biopsy in the office setting.
• Saline infusion sonohysterography can better characterize intracavitary lesions, while hysteroscopy allows direct visualization and targeted biopsy of the endometrial cavity.
• MRI may be useful in complex cases, and laboratory evaluation should be tailored to the suspected etiology, with additional testing such as prolactin levels or androgen panels if conditions like hyperprolactinemia or polycystic ovary syndrome are suspected. The most recent and highest quality study recommends that if the uterus is incompletely visualized with the initial ultrasound, MRI of the pelvis without and with contrast is the next appropriate imaging study, unless a polyp is suspected on the original ultrasound, then sonohysterography can be performed 1.

From the Research

Evaluation of Abnormal Uterine Bleeding (AUB)

The workup for abnormal uterine bleeding (AUB) involves a systematic approach to identify the underlying cause of the bleeding. The following steps are involved in the evaluation of AUB:

• Eliciting a focused menstrual history to determine the pattern and characteristics of the bleeding 2, 3
• Performing a pelvic examination, including a vaginal speculum examination, to differentiate anovulatory bleeding from other causes of bleeding 2
• Using the PALM-COEIN classification system to categorize the cause of AUB, which includes:
  • Polyp
  • Adenomyosis
  • Leiomyoma
  • Malignancy and hyperplasia
  • Coagulopathy
  • Ovulatory dysfunction
  • Endometrial
  • Iatrogenic
  • Not yet classified 2, 3, 4
• Imaging studies, such as pelvic ultrasound, to identify structural causes of AUB, such as fibroids, adenomyosis, and endometrial polyps 5, 6
• Endometrial sampling, which may be performed in patients who are at high risk for endometrial cancer or in patients who do not respond to medical treatment 4

Imaging Studies

Imaging studies play a crucial role in the evaluation of AUB. The following imaging modalities may be used:

• Pelvic ultrasound: This is the initial and often only imaging modality needed to evaluate AUB, and can accurately identify common causes of abnormal uterine bleeding in reproductive-aged women 5
• Saline infusion sonohysterography: This can help to triage patients and identify focal abnormalities that require further evaluation 6

Diagnostic Approach

The diagnostic approach to AUB involves a combination of clinical evaluation, imaging studies, and endometrial sampling. The goal is to identify the underlying cause of the bleeding and develop an effective treatment plan. The PALM-COEIN classification system provides a framework for categorizing the cause of AUB and guiding the diagnostic approach 2, 3, 4