What is the initial workup for a patient presenting with irregular menstrual bleeding?

Initial Workup for Irregular Menstrual Bleeding

The initial workup for irregular menstrual bleeding should include a thorough history, physical examination with pelvic assessment, laboratory tests, and transvaginal ultrasonography to identify the underlying cause and guide appropriate management. 1

Diagnostic Approach

History and Physical Examination

• Bleeding pattern assessment:

  • Duration, frequency, volume, and regularity of bleeding
  • Presence of intermenstrual bleeding
  • Associated symptoms (pain, dysmenorrhea)
  • Timing in relation to menstrual cycle

• Risk factor assessment:

  • Age (higher risk of endometrial cancer in perimenopausal women)
  • Obesity
  • Polycystic ovary syndrome
  • Thyroid dysfunction
  • Coagulation disorders
  • Medication use (anticoagulants, hormonal contraceptives)

• Physical examination:

  • Vital signs to assess hemodynamic stability
  • BMI calculation
  • Pelvic examination including speculum examination
  • Pap smear according to screening guidelines 1

Laboratory Testing

1. Complete blood count (CBC) - to assess for anemia and platelet abnormalities 2
2. Pregnancy test - to rule out pregnancy-related bleeding 1, 3
3. Thyroid function tests - to evaluate for thyroid dysfunction 4
4. Coagulation studies - particularly if heavy bleeding or family history of bleeding disorders (von Willebrand disease is most common) 4
5. Prolactin levels - if irregular cycles suggest anovulation 4
6. Blood typing and cross-matching - if severe bleeding present 2

Imaging

• Transvaginal ultrasonography - recommended as first-line imaging for all women with abnormal uterine bleeding 2, 3

  • Evaluates endometrial thickness
  • Identifies structural abnormalities (fibroids, polyps, adenomyosis)
  • Assesses ovaries for cysts or polycystic morphology

• Saline infusion sonohysterography - second-line imaging if initial ultrasound is inconclusive or suggests intracavitary lesions 2

• MRI - not recommended as first-line but may be considered when ultrasound is inadequate or inconclusive, especially for evaluating adenomyosis or complex fibroids 2

Endometrial Assessment

• Endometrial biopsy is indicated for:

  • Women ≥35 years with recurrent anovulatory bleeding
  • Women <35 years with risk factors for endometrial cancer
  • Persistent abnormal bleeding unresponsive to medical therapy
  • Suspected endometrial hyperplasia or malignancy 4

• Hysteroscopy - second-line procedure for direct visualization of the endometrial cavity when other evaluations are inconclusive 3

Classification Framework

Use the PALM-COEIN classification system to categorize causes of abnormal uterine bleeding 1:

• Structural causes (PALM):

  • Polyps
  • Adenomyosis
  • Leiomyoma (fibroids)
  • Malignancy and hyperplasia

• Non-structural causes (COEIN):

  • Coagulopathy
  • Ovulatory dysfunction
  • Endometrial
  • Iatrogenic
  • Not otherwise classified

Special Considerations

• Unexplained vaginal bleeding requires thorough evaluation before starting hormonal treatments, as these may mask underlying pathology 2

• Undiagnosed breast masses should be evaluated before initiating hormonal therapy 2

• Heavy or prolonged bleeding should raise suspicion for serious underlying conditions 2

• Perimenopausal women have higher risk of endometrial hyperplasia/cancer and require lower threshold for endometrial sampling 1

Common Pitfalls to Avoid

• Failing to rule out pregnancy before initiating workup
• Overlooking coagulation disorders in women with heavy menstrual bleeding
• Initiating hormonal treatment without adequate evaluation for structural causes
• Neglecting endometrial sampling in women at risk for endometrial hyperplasia or cancer
• Failing to consider medication side effects as potential causes of irregular bleeding

By following this systematic approach to the initial workup of irregular menstrual bleeding, clinicians can effectively identify the underlying cause and develop an appropriate management plan to reduce morbidity and improve quality of life.