What is the initial approach to managing a patient with Abnormal Uterine Bleeding - Anovulatory (AUB-A)?

Initial Management of Abnormal Uterine Bleeding - Anovulatory (AUB-A)

The initial approach to managing AUB-A should begin with transvaginal ultrasound (TVUS) combined with transabdominal ultrasound as the first-line imaging modality, followed by hormonal therapy with either combined oral contraceptives or progestins based on the patient's age and risk factors. 1, 2

Diagnostic Evaluation

Step 1: Imaging Assessment

• First-line imaging: Combined transabdominal and transvaginal ultrasound with color Doppler

  • TVUS provides higher resolution for endometrial assessment
  • Transabdominal approach helps with overall assessment, especially in obese patients
  • Color Doppler helps evaluate vascularity of findings 1, 2

• If TVUS is inconclusive:

  • Proceed to saline infusion sonohysterography (SIS) if focal endometrial abnormality is suspected
  • SIS can distinguish between leiomyomas and endometrial polyps with 97% accuracy 1
  • Consider MRI with diffusion-weighted imaging if endometrium cannot be adequately visualized 2

Step 2: Endometrial Sampling

• Indications for endometrial biopsy:
  • Women over 40 years old
  • Women with obesity (due to increased risk of endometrial hyperplasia and cancer)
  • Recurrent anovulation
  • Women younger than 35 with risk factors for endometrial cancer
  • Excessive bleeding unresponsive to medical therapy 2, 3

Treatment Algorithm

For Adolescents with AUB-A:

• First-line: Medroxyprogesterone acetate 10 mg daily for 10 days each month for ≥3 months with close monitoring thereafter 4
• Alternative: Combined oral contraceptives if contraception is also desired 3

For Reproductive-Age Women with AUB-A:

• If contraception is desired: Combined oral contraceptives 3
• If pregnancy is desired: Clomiphene citrate to induce ovulation 4
• If neither is a priority: Oral medroxyprogesterone acetate 10 days each month for 6 months 4

For Perimenopausal Women with AUB-A:

• First-line options:
  • Cyclic progestin therapy
  • Cyclic conjugated equine estrogens for 25 days with medroxyprogesterone acetate for days 18-25
  • Low-dose combination oral contraceptives (for non-smokers without vascular disease) 4

For Severe Acute Bleeding Episodes:

• Medical management: High-dose estrogen therapy 4
• If hypovolemia present: Consider dilation and curettage 4

Special Considerations

Monitoring Response

• Reassess bleeding pattern after 3 months of therapy
• If endometrial sampling was performed, follow up based on histologic findings:
  • Hyperplasia without atypia: Treat with cyclic or continuous progestin
  • Hyperplasia with atypia or adenocarcinoma: Refer to gynecologist or gynecologic oncologist 3

Common Pitfalls to Avoid

• Failure to perform endometrial sampling in high-risk women
• Inadequate imaging assessment
• Assuming perimenopause as the only cause of AUB
• Delaying evaluation in women with risk factors
• Incomplete visualization during ultrasound examination 2
• Missing underlying bleeding disorders (present in ~20% of patients with heavy menstrual bleeding) 5

When to Consider Alternative Diagnoses

• Evaluate for both structural and non-structural causes using the PALM-COEIN classification:
  • Polyp(s), Adenomyosis, Leiomyoma, Malignancy (structural)
  • Coagulopathy, Ovulatory dysfunction, Endometrial disorders, Iatrogenic, Not yet classified (non-structural) 2, 6
• Consider screening for von Willebrand disease, especially if heavy bleeding has been present since menarche 5, 4
• Rule out endocrine disorders such as hypothyroidism, hyperprolactinemia, and polycystic ovary syndrome 5, 3