What are the current guidelines for evaluating and managing abnormal uterine bleeding in women?

Abnormal Uterine Bleeding Guidelines

Begin evaluation with pregnancy testing, followed by systematic classification using the PALM-COEIN system to distinguish structural causes (Polyp, Adenomyosis, Leiomyoma, Malignancy/hyperplasia) from nonstructural causes (Coagulopathy, Ovulatory dysfunction, Endometrial, Iatrogenic, Not classified), then proceed with transvaginal ultrasound as first-line imaging. 1, 2

Initial Assessment

Critical First Steps

• Rule out pregnancy immediately with beta-hCG testing 2
• Assess hemodynamic stability - check for signs of hypovolemia requiring urgent intervention 3
• Obtain complete blood count to evaluate for anemia
• Measure TSH and prolactin levels to identify thyroid disease and hyperprolactinemia 2

Risk Stratification for Endometrial Cancer

Endometrial biopsy is indicated when:

• Age >45 years with AUB
• Age <45 years with risk factors: obesity, PCOS, unopposed estrogen exposure, tamoxifen use, Lynch syndrome, or failed medical management 2

Common pitfall: Do not perform routine endometrial biopsy in young women without risk factors - this is unnecessary and increases cost without improving outcomes.

Imaging Strategy

First-Line: Transvaginal Ultrasound

Transvaginal ultrasound (TVUS) is the initial imaging modality of choice for evaluating structural abnormalities 1, 2. It effectively identifies:

• Endometrial polyps
• Submucosal and intramural fibroids
• Adenomyosis
• Endometrial thickness abnormalities

Limitations requiring alternative imaging:

• Uterine position preventing adequate visualization
• Patient body habitus obscuring views
• Large fibroids or adenomyosis preventing complete endometrial assessment 1

When TVUS is Inadequate

MRI with diffusion-weighted imaging should be obtained when:

• TVUS cannot completely visualize the endometrium
• Precise fibroid mapping needed for surgical planning
• Differentiating adenomyosis from fibroids
• Concern for leiomyosarcoma versus benign leiomyoma 1

The multiplanar capability and superior tissue contrast of MRI allows endometrial visualization even with extensive myometrial pathology 1.

Saline infusion sonohysterography has 96-100% sensitivity for intracavitary lesions and serves as an excellent alternative when TVUS is equivocal 2.

Management Algorithm

Medical Management (First-Line for Most Patients)

For acute, heavy bleeding requiring urgent control:

1. Intravenous conjugated equine estrogen (25 mg IV every 4-6 hours until bleeding stops, maximum 24 hours)
2. High-dose combined oral contraceptives (monophasic pill with 30-35 mcg ethinyl estradiol, one pill three times daily for 7 days)
3. Oral progestins (medroxyprogesterone 20 mg three times daily for 7 days)
4. Tranexamic acid (1300 mg three times daily for up to 5 days) 3

For chronic AUB with ovulatory dysfunction:

• Combined hormonal contraceptives (pills, patch, or ring) - first choice for contraception-seeking patients
• Progestin-only options (oral, depot injection, or levonorgestrel IUD) - preferred when estrogen contraindicated 2

Critical consideration: Base medication choice on contraindications - avoid estrogen in patients with thromboembolism history, migraine with aura, or cardiovascular disease.

Surgical Management Indications

Proceed directly to surgery when:

• Hemodynamically unstable despite resuscitation
• Medical management contraindicated
• Failed adequate trial of medical therapy (typically 3-6 months)
• Significant intracavitary structural lesions identified (submucosal fibroids, large polyps) 2

Surgical options by pathology:

• Endometrial polyps: Hysteroscopic polypectomy
• Type 0-2 submucosal fibroids: Hysteroscopic myomectomy
• Type 3+ fibroids: Abdominal/laparoscopic myomectomy or uterine artery embolization
• Failed medical management without desire for fertility: Endometrial ablation
• Definitive treatment: Hysterectomy for completed childbearing 2

Special Populations

Adolescents

Anovulation is the predominant cause in this age group. Screen for bleeding disorders (von Willebrand disease, platelet dysfunction) in adolescents with heavy menstrual bleeding since menarche, particularly if requiring hospitalization or transfusion 2.

Perimenopausal Women

Higher risk for endometrial hyperplasia and malignancy. Lower threshold for endometrial sampling - perform biopsy for any irregular bleeding pattern 2.

Postmenopausal Women

Any postmenopausal bleeding requires endometrial evaluation - endometrial cancer is the primary concern. TVUS showing endometrial thickness <4-5 mm has high negative predictive value, but biopsy remains gold standard 1.

Maintenance Therapy

After controlling acute bleeding, transition to long-term maintenance to prevent recurrence 3:

• Levonorgestrel IUD (most effective for reducing menstrual blood loss)
• Combined hormonal contraceptives
• Cyclic or continuous oral progestins
• Tranexamic acid during menses only

The levonorgestrel IUD reduces menstrual blood loss by 71-95% and should be strongly considered for women desiring long-term management without surgical intervention.