What is the recommended evaluation and initial management for abnormal uterine bleeding in a reproductive‑age woman?

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Evaluation and Initial Management of Abnormal Uterine Bleeding in Reproductive-Age Women

Begin with a urine pregnancy test, followed by transvaginal ultrasound as the first-line imaging study, then proceed to endometrial biopsy if the patient is ≥45 years old, has risk factors for endometrial cancer, or demonstrates concerning ultrasound findings; for medical management, the levonorgestrel-releasing intrauterine device is the most effective first-line treatment. 1, 2


Initial Assessment and Risk Stratification

Immediate Evaluation Steps

  • Perform a urine β-hCG test first to exclude pregnancy in all reproductive-age women presenting with abnormal bleeding, as pregnancy-related bleeding requires a completely different diagnostic and management pathway. 1, 3

  • Assess hemodynamic stability by checking vital signs and asking whether bleeding saturates a large pad or tampon hourly for ≥4 hours, which warrants urgent evaluation. 3

  • Obtain a complete blood count to assess for anemia and thrombocytopenia, which may indicate either the severity of blood loss or an underlying coagulopathy. 2, 3

  • Order thyroid-stimulating hormone (TSH) and prolactin levels to screen for endocrine causes of ovulatory dysfunction, particularly in women with irregular cycles. 1, 3


Diagnostic Imaging Algorithm

First-Line: Transvaginal Ultrasound

  • Transvaginal ultrasound combined with transabdominal imaging is the recommended initial diagnostic test for all reproductive-age women with abnormal uterine bleeding, receiving the highest appropriateness rating (7–9) from the American College of Radiology. 1, 3

  • TVUS reliably distinguishes structural causes—including polyps, adenomyosis, leiomyomas, endometrial hyperplasia, and malignancy—from non-structural causes such as ovulatory dysfunction or coagulopathy. 1

  • The ultrasound should systematically assess endometrial thickness, texture, echogenicity, and the presence of focal lesions to fully evaluate pelvic structures. 1

  • Perform the scan during the early proliferative phase (days 4–6) when the endometrium is thinnest, to optimize visualization and avoid false-positive findings from physiologic thickening. 1

Advanced Imaging When Indicated

  • Saline infusion sonohysterography (SIS) should be performed when focal lesions are suspected or when standard TVUS inadequately visualizes the endometrium, offering 96–100% sensitivity and 94–100% negative predictive value for detecting endometrial pathology. 1, 3

  • SIS can distinguish polyps from submucous fibroids with 97% accuracy, making it superior to blind endometrial sampling for focal lesions. 3

  • If TVUS cannot adequately visualize the endometrium due to body habitus, uterine position, or interfering pathology (large fibroids, adenomyosis), proceed directly to endometrial sampling rather than relying on the incomplete scan. 1


Indications for Endometrial Biopsy

Age-Based Criteria

  • All women ≥45 years with abnormal uterine bleeding require endometrial sampling regardless of ultrasound findings, based on high-quality guideline evidence from ACOG, NCCN, and ESMO. 1

  • In perimenopausal women, anovulatory cycles become increasingly common, resulting in unopposed estrogen exposure that markedly raises the risk of endometrial hyperplasia and carcinoma. 1

Risk Factor–Based Criteria (Age <45 Years)

  • Perform endometrial biopsy in women <45 years if they have risk factors for endometrial cancer, including:
    • Long-standing unopposed estrogen exposure (PCOS, chronic anovulation)
    • Obesity (BMI ≥30 kg/m²)
    • Diabetes mellitus or hypertension
    • Tamoxifen therapy
    • Lynch syndrome or family history of endometrial cancer
    • Persistent or recurrent bleeding despite initial treatment 1

Ultrasound-Based Criteria

  • Endometrial biopsy is indicated when TVUS shows endometrial thickness ≥10 mm in premenopausal women with risk factors, or when focal lesions are identified. 1

  • Ultrasound alone cannot differentiate hyperplasia, polyps, or malignancy; therefore, histologic tissue sampling remains necessary for definitive diagnosis when structural abnormalities are detected. 1

Technique and Follow-Up

  • Office endometrial biopsy using Pipelle or Vabra devices achieves sensitivity of 99.6% and 97.1% respectively for detecting endometrial carcinoma when adequate tissue is obtained. 1

  • Office endometrial biopsies have a 10% false-negative rate, so if the initial biopsy is negative, inadequate, or non-diagnostic but symptoms persist, escalate to hysteroscopy with directed biopsy or fractional D&C under anesthesia. 1, 2


Classification of Causes: PALM-COEIN System

Structural Causes (PALM)

  • Polyp: Common in women >40 years; detected by SIS or hysteroscopy 3
  • Adenomyosis: Frequently coexists with fibroids; presents with heavy bleeding, dysmenorrhea, and dyspareunia in women in their 40s 2, 3
  • Leiomyoma (fibroids): Most common structural cause in women <40 years 3
  • Malignancy/hyperplasia: Most serious etiology; requires tissue diagnosis 3

Non-Structural Causes (COEIN)

  • Coagulopathy: Consider in adolescents or women with lifelong heavy bleeding; may require hematology referral 3
  • Ovulatory dysfunction: Irregular, unpredictable bleeding; common in perimenopause and PCOS 3
  • Endometrial: Primary endometrial disorders affecting hemostasis 3
  • Iatrogenic: Anticoagulation (70% of women on anticoagulants experience heavy bleeding), copper IUD, hormonal contraceptives 3
  • Not yet classified: Other causes not fitting above categories 3

Medical Management Algorithm

First-Line Treatment

  • The levonorgestrel-releasing intrauterine device (LNG-IUD) is the most effective first-line medical treatment, reducing menstrual blood loss by 71–95% with efficacy comparable to endometrial ablation. 2

  • The LNG-IUD is particularly preferred in women with cardiovascular disease or those on anticoagulation, as it has minimal systemic absorption and avoids the thrombotic risk associated with combined hormonal contraceptives, NSAIDs, and tranexamic acid. 2, 3

Alternative Hormonal Options

  • Combined hormonal contraceptives (CHCs) are effective for ovulatory dysfunction bleeding and can be combined with NSAIDs to further reduce bleeding volume. 2

  • Oral progestins administered for 21 days per month reduce menstrual blood loss and are effective for women with cyclic heavy bleeding related to the menstrual cycle. 2

Non-Hormonal Options

  • Tranexamic acid is a viable option for heavy menstrual bleeding with high efficacy, but should be avoided in women with cardiovascular disease or thrombotic risk. 2, 3

  • NSAIDs may be utilized with hormonal methods to decrease menstrual bleeding, but are contraindicated in women with cardiovascular disease or post-SCAD due to MI risk. 2, 3


Surgical Management

Indications for Surgical Intervention

  • If bleeding persists despite initial medical therapy, further investigation with hysteroscopy is indicated to diagnose focal lesions possibly missed by endometrial sampling. 2

  • Endometrial ablation is a less invasive alternative to hysterectomy with efficacy comparable to LNG-IUD, but requires thorough informed consent regarding long-term complications including postablation Asherman syndrome, synechiae, cervical stenosis, and potential delayed endometrial cancer diagnosis. 2, 3

  • Hysterectomy is the most appropriate treatment when medical management fails or is contraindicated, particularly in women who have completed childbearing and desire permanent resolution, providing complete symptom resolution and significantly better health-related quality of life. 2, 3


Special Populations and Pitfalls

Women on Anticoagulation

  • Approximately 70% of women on anticoagulation therapy experience heavy menstrual bleeding, with oral anticoagulants causing abnormal bleeding in 9–14% of reproductive-age women. 3

  • Reassess the indication for ongoing antiplatelet therapy and discontinue if appropriate before initiating AUB treatment; progestin-eluting IUDs are preferred due to minimal systemic absorption. 2, 3

Lynch Syndrome Carriers

  • Women with Lynch syndrome have a 30–60% lifetime risk of endometrial cancer and should undergo annual endometrial biopsy screening starting at age 30–35 years. 1

  • Any abnormal bleeding in a Lynch syndrome carrier mandates immediate endometrial biopsy to rule out cancer, regardless of age or ultrasound findings. 1

Common Diagnostic Pitfalls

  • Never accept an inadequate or negative endometrial biopsy as reassuring in a symptomatic woman, especially one ≥45 years or with risk factors—persistent bleeding mandates escalation to hysteroscopy or D&C. 1

  • Endometrial biopsy alone should not be used to rule out focal lesions, as it has variable sensitivity; SIS or hysteroscopy is required when polyps or submucous fibroids are suspected. 2

  • Do not initiate hormonal therapy before obtaining TVUS in women ≥45 years or those with risk factors, as this may mask or delay the diagnosis of endometrial cancer. 1


Referral Criteria

  • Refer to gynecology when:
    • Medical management fails after 3–6 months
    • Endometrial sampling shows hyperplasia or malignancy
    • Postmenopausal bleeding with endometrial thickness ≥4 mm
    • Persistent bleeding despite negative initial workup 3

References

Guideline

Indications for Endometrial Biopsy

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

Guideline

Management of Abnormal Uterine Bleeding

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Initial Management of Abnormal Uterine Bleeding

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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