What is the initial approach for managing abnormal uterine bleeding (AUB) as assessed by an International Endocervical Tubal Abnormality (IETA) AUB calculator?

Initial Approach for Managing Abnormal Uterine Bleeding (AUB)

Transvaginal ultrasound (TVUS) combined with transabdominal ultrasound is the recommended first-line imaging modality for the initial evaluation of abnormal uterine bleeding. 1, 2

Imaging Approach

First-Line Imaging

• Combined approach: TVUS + transabdominal ultrasound
  • TVUS provides higher resolution for endometrial assessment
  • Transabdominal approach helps with overall assessment, especially with enlarged uterus or when the field of view of TVUS is limited 1
  • Color and spectral Doppler should be included as standard components to evaluate vascularity of findings 1, 2

When Initial Ultrasound is Inconclusive

If the endometrium cannot be adequately visualized with TVUS:

1. Sonohysterography (saline infusion sonography)

   • Particularly useful when TVUS shows a focal endometrial abnormality 1
   • Involves transcervical injection of sterile saline with TVUS 1

2. MRI with diffusion-weighted imaging

   • Recommended when ultrasound is inconclusive 1, 2
   • Diffusion-weighted imaging improves sensitivity and specificity for accurate diagnosis of uterine pathology 1
   • MRI can display the endometrium even with coexisting leiomyomas and adenomyosis 1

Evaluation for Structural and Non-Structural Causes

Structural Causes (PALM)

• Polyps: Look for vascular pedicle during transvaginal color Doppler imaging (specificity 62-98%) 1
• Adenomyosis: TVUS sensitivity 82.5% and specificity 84.6% (lower if coexisting leiomyomas present) 1
• Leiomyomas: Assess size, location, and impact on endometrium
• Malignancy/Hyperplasia: Evaluate endometrial thickness and texture

Non-Structural Causes (COEIN)

• Coagulopathy: Consider in heavy menstrual bleeding, especially in adolescents
• Ovulatory dysfunction: Common in perimenopause
• Endometrial causes: Assess endometrial thickness and pattern
• Iatrogenic causes: Review medication history

Endometrial Thickness Assessment

• Postmenopausal women:

  • Endometrial thickness ≤4 mm has negative predictive value for cancer of nearly 100% 1
  • Thickness ≥5 mm generally requires endometrial tissue sampling 1

• Premenopausal women:

  • Normal thickness varies with menstrual cycle phase
  • No validated absolute upper limit cutoff 1
  • Thickness <5 mm does not exclude endometrial pathology 1

Management Based on Findings

Medical Management (First-Line Approach)

After excluding significant structural causes:

• Levonorgestrel-releasing intrauterine system - highest efficacy for heavy menstrual bleeding 2, 3
• Combined oral contraceptives - effective for regulating bleeding patterns 3, 4
• Oral progestins - can be used continuously 3, 5
• Tranexamic acid - effective non-hormonal option, especially when hormonal treatments are contraindicated 3, 5
• NSAIDs - can be used with hormonal methods to decrease bleeding 3

Acute Heavy Bleeding Management

• Parenteral estrogen (IV conjugated equine estrogen)
• Multi-dose combined oral contraceptive regimen
• Multi-dose progestin-only regimen
• Tranexamic acid 3, 4

Common Pitfalls to Avoid

• Failure to perform endometrial sampling in women over 40 years or with risk factors 2
• Inadequate imaging or incomplete visualization of the endometrium 2
• Assuming perimenopause as the only cause of AUB without proper evaluation 2
• Delaying evaluation, especially in women with risk factors for endometrial cancer 2
• Failing to consider both structural and non-structural causes 2

Special Considerations

• Women over 40: Higher risk of endometrial hyperplasia and cancer; endometrial biopsy recommended 2
• Obesity: Increases risk of endometrial cancer; more thorough evaluation needed 2
• Women with inherited bleeding disorders: All hormonal methods and tranexamic acid can be used 3
• Women on anticoagulation therapy: Consider progestin-only methods 3

The IETA AUB calculator should be used as part of this comprehensive evaluation approach to guide appropriate management decisions based on patient-specific factors and imaging findings.