What are the recommended evaluation and management guidelines for abnormal uterine bleeding (AUB) in reproductive‑age women?

Management of Abnormal Uterine Bleeding in Reproductive-Age Women

Begin evaluation with a detailed menstrual history documenting bleeding patterns, pregnancy testing, and assessment for structural versus nonstructural causes using the PALM-COEIN classification system, followed by transvaginal ultrasound as first-line imaging and hormonal therapy as first-line treatment for most cases. 1, 2

Initial Evaluation Framework

History and Physical Examination

• Document specific bleeding characteristics: frequency, duration, volume, regularity, and relationship to menstrual cycle 3
• Screen for coagulopathies: family history of bleeding disorders, personal history of excessive bleeding with dental procedures, childbirth, or surgery 1, 4
• Assess for ovulatory dysfunction indicators: age (adolescence or perimenopause), lactation, hyperandrogenic features, thyroid symptoms, galactorrhea 1
• Identify risk factors for endometrial malignancy: age >45 years, obesity, diabetes, PCOS, unopposed estrogen exposure, tamoxifen use, Lynch syndrome 1, 4

Laboratory Testing

• Mandatory initial tests: pregnancy test (beta-hCG), complete blood count to assess anemia 1, 4
• Selective testing based on clinical suspicion: TSH and prolactin for ovulatory dysfunction, coagulation studies if bleeding disorder suspected 1, 4

Imaging Strategy

• Transvaginal ultrasound is the first-line imaging modality for all reproductive-age women with AUB (except virgins, who should receive transabdominal imaging) 1, 2
• Saline infusion sonohysterography has 96-100% sensitivity for detecting intracavitary lesions and should be used when transvaginal ultrasound is inconclusive or suggests focal pathology 1
• Hysteroscopy is reserved for failed medical treatment or when focal lesions are suspected but not adequately visualized on ultrasound 1

Endometrial Sampling

• Endometrial biopsy is indicated only when additional risk factors for endometrial cancer are present, not routinely for all AUB cases 2, 4
• Preferred over dilation and curettage due to lower invasiveness, better safety profile, and lower cost 1
• Important caveat: sensitivity is reduced for focal lesions (polyps, submucosal fibroids), so negative biopsy does not exclude pathology if imaging suggests structural abnormality 1

PALM-COEIN Classification Application

The FIGO classification divides causes into structural (PALM) and nonstructural (COEIN) categories 1, 3:

Structural Causes (PALM)

• Polyp
• Adenomyosis
• Leiomyoma (submucosal or other)
• Malignancy and hyperplasia

Nonstructural Causes (COEIN)

• Coagulopathy
• Ovulatory dysfunction (most common identifiable cause at 31.6%) 1, 5
• Endometrial disorders
• Iatrogenic (including anticoagulant-related bleeding)
• Not yet classified

Treatment Algorithm

First-Line Medical Management

Hormonal treatments should be initiated as first-line therapy for AUB without significant structural pathology 1, 2, 6:

• Combined oral contraceptive pills are associated with improved outcomes (OR 2.15, p<0.001) and reduced anemia prevalence 5
• Levonorgestrel-releasing intrauterine system (LNG-IUS) is highly effective, particularly for heavy menstrual bleeding, and commonly achieves amenorrhea 7
• Progestin-only contraception is an alternative when estrogen is contraindicated 1

Nonhormonal Options

• Tranexamic acid is effective for heavy menstrual bleeding and can be combined with hormonal therapy 7
• NSAIDs reduce menstrual blood loss but are less effective than hormonal treatments 4

Special Population: Bleeding Disorders

• LNG-IUS as first-line, followed by tranexamic acid or desmopressin (DDAVP) for patients with inherited bleeding disorders 7
• Combination therapy often achieves amenorrhea in this population 7

Special Consideration: Anticoagulant Users

• Rivaroxaban carries the highest risk of AUB among oral anticoagulants 8
• Women <50 years have greater relative increase in AUB (19.7% vs 9.2%) compared to women ≥50 years (3.8% vs 2.0%) when on anticoagulation 8
• AUB incidence is significantly higher in anticoagulant users (6.1% vs 3.0%, AOR 1.81) 8

Surgical Management Indications

Surgery should be considered when medical treatment fails, is contraindicated, not tolerated, or when significant intracavitary lesions are present 1, 6:

Surgical Options by Indication

• Identified polyps or large fibroids: hysteroscopic polypectomy or myomectomy 2, 6
• Type 0-2 fibroids (submucosal): hysteroscopic resection 6
• Failed medical management: endometrial ablation or hysterectomy 1, 4

Endometrial Ablation Considerations

• Not a first-line option but should be discussed with appropriate candidates 1
• Long-term complications include postablation Asherman syndrome, synechiae, cervical stenosis, endometrial contracture, and potential delayed diagnosis of endometrial cancer 1
• Requires thorough informed consent and counseling 1

Predictors of Treatment Response

Age and BMI significantly influence treatment outcomes 5:

• Younger age decreases odds of treatment success (OR 0.95, p=0.015) 5
• Higher BMI increases likelihood of response (OR 1.10, p=0.005) 5
• Presence of leiomyoma decreases treatment success (OR 0.55, p=0.007) 5
• Ovulatory dysfunction increases likelihood of response to medical therapy (OR 1.75, p=0.003) 5

Critical Pitfalls to Avoid

• Do not perform routine endometrial biopsy in women <45 years without additional risk factors for endometrial cancer 2, 4
• Do not rely solely on endometrial biopsy to exclude focal lesions—imaging is essential 1
• Do not use transvaginal ultrasound in virgins; transabdominal imaging is appropriate 1
• Do not delay investigation with imaging or hysteroscopy if medical treatment fails 1
• Do not overlook coagulopathy screening in adolescents or women with heavy bleeding since menarche 1, 4