What are the guidelines for managing Abnormal Uterine Bleeding (AUB)?

Management of Abnormal Uterine Bleeding

The levonorgestrel-releasing intrauterine device (LNG-IUD) is the most effective first-line medical treatment for abnormal uterine bleeding, reducing menstrual blood loss by 71-95% with efficacy comparable to endometrial ablation. 1, 2

Initial Diagnostic Workup

Mandatory First Steps

• Pregnancy test is mandatory in all reproductive-age women before any evaluation or treatment 1, 2
• Obtain complete blood count with platelets to assess for anemia and thrombocytopenia 2
• Measure thyroid-stimulating hormone and prolactin levels to exclude thyroid dysfunction and hyperprolactinemia 2
• Document detailed menstrual history including regularity, duration, frequency, and volume of bleeding 2
• Assess for signs of hyperandrogenism (acne, hirsutism) suggesting polycystic ovary syndrome 2

Classification System

• Use the PALM-COEIN classification system to categorize bleeding causes 1, 2
  • Structural causes (PALM): Polyp, Adenomyosis, Leiomyoma, Malignancy/Hyperplasia 1, 2
  • Non-structural causes (COEIN): Coagulopathy, Ovulatory dysfunction, Endometrial, Iatrogenic, Not yet classified 1, 2

Imaging Strategy

First-Line Imaging

• Perform combined transabdominal and transvaginal ultrasound with Doppler as first-line imaging for all patients 3, 2
• Transvaginal ultrasound detects both benign endometrial and myometrial pathologies including endometrial hyperplasia, polyps, adenomyosis, and leiomyomas 3
• Transabdominal ultrasound is essential when the uterus is significantly enlarged, as transvaginal ultrasound has limited field of view 3

Advanced Imaging When Indicated

• Use saline infusion sonohysterography when initial ultrasound is inconclusive or further characterization is needed, with sensitivity of 96-100% and negative predictive value of 94-100% for assessing intracavitary pathology 2, 4
• MRI pelvis is reserved for preprocedural workup of leiomyomas prior to uterine artery embolization to map vascular anatomy 3
• Doppler imaging helps identify vessels within endometrial polyps or cancer, with vascular pedicle visualization having 62-98% specificity for detecting endometrial polyps 3

Endometrial Sampling Indications

• In postmenopausal women, endometrial thickness ≥5 mm on transvaginal ultrasound mandates endometrial tissue sampling, while thickness <4 mm has nearly 100% negative predictive value for cancer 2
• Perform endometrial biopsy in premenopausal women aged ≥35 years with persistent abnormal bleeding or risk factors for endometrial cancer (unopposed estrogen exposure, tamoxifen therapy, anovulation, nulliparity, diabetes, hypertension) 4
• Pipelle or Vabra devices have extremely high sensitivity (99.6% and 97.1% respectively) for detecting endometrial carcinoma 4

Medical Management Algorithm

First-Line Treatment

• Levonorgestrel-releasing IUD (LNG-IUD) is the most effective first-line option, reducing menstrual blood loss by 71-95% 1, 2
• LNG-IUD efficacy is equivalent to endometrial ablation 1, 2

Alternative Hormonal Options

• Combined hormonal contraceptives (CHCs) are effective for ovulatory dysfunction bleeding and can be combined with NSAIDs to further reduce bleeding volume 1, 2
• Oral progestins administered for 21 days per month reduce menstrual blood loss and are effective for women with cyclic heavy bleeding 1, 2
• In acute abnormal uterine bleeding, use multidose combined oral contraceptive regimen, multidose progestin-only regimen, or parenteral estrogen 5

Non-Hormonal Options

• Tranexamic acid is a viable option with high efficacy for heavy menstrual bleeding, reducing flow by approximately 50% 1, 2, 6
• NSAIDs decrease bleeding by 30-50% and may be utilized with hormonal methods 1, 2, 6

Special Population: Cardiovascular Disease

• In patients with cardiovascular disease or post-SCAD, NSAIDs and tranexamic acid must be avoided due to MI and thrombosis risk—the LNG-IUD becomes the mandatory preferred option 1, 2
• For patients on antiplatelet therapy, reassess the indication and discontinue if appropriate before initiating treatment, with progestin-eluting IUDs preferred due to minimal systemic absorption 1

Preoperative Medical Management for Fibroids

• Consider 1-2 courses of ulipristal acetate (UPA) to bridge to surgery, improve quality of life, and shrink fibroids when surgery is delayed for several months 3
• UPA pretreatment may facilitate minimally invasive surgical approach and does not increase difficulty of hysteroscopic or laparoscopic myomectomy 3
• Clinical trial data demonstrated fibroid volume reductions of approximately 30% after a single UPA course and up to 70% after 4 courses 3

Surgical Management

When to Escalate to Surgery

• If bleeding persists despite initial medical therapy, perform hysteroscopy to visualize the endometrial cavity and diagnose focal lesions potentially missed by endometrial sampling 1, 2
• Office endometrial biopsies have a false-negative rate of approximately 10%, requiring follow-up with fractional D&C under anesthesia if negative but symptoms persist 4

Surgical Options

• Endometrial ablation is a less invasive alternative to hysterectomy with efficacy comparable to LNG-IUD 1, 2
• Provide thorough informed consent regarding long-term complications of endometrial ablation, including postablation Asherman syndrome, synechiae, cervical stenosis, and potential delayed endometrial cancer diagnosis 1
• Hysterectomy is the definitive treatment when medical management fails or is contraindicated, particularly in postmenopausal women with symptomatic fibroids 1, 2

Myomectomy Considerations

• For patients desiring fertility with fibroids, myomectomy type and route depend on fibroid size and myoma-serosa distance 3
• After UPA treatment, image the uterine cavity as part of preoperative workup, as UPA can induce fibroid migration 3
• If cavity is normal after UPA treatment, patient may attempt natural or assisted conception without surgery 3

Common Pitfalls and Caveats

Diagnostic Pitfalls

• Never accept an inadequate or negative endometrial biopsy as reassuring in a symptomatic postmenopausal woman—persistent bleeding mandates further evaluation with D&C or hysteroscopy 4
• Endometrial biopsy alone should not be used to rule out focal lesions, as it has variable sensitivity 1
• A negative biopsy does not rule out pathology if symptoms persist, given the 10% false-negative rate 4

Treatment Pitfalls

• In perimenopausal women, pulsatile courses of UPA can help transition into menopause while avoiding surgery, restarting when symptoms recur 3
• Although UPA inhibits ovulation, an ovulation rate of up to 20% occurs at fibroid-treatment doses—counsel patients about concurrent nonhormonal contraception 3
• For women with Lynch syndrome, perform annual endometrial biopsy surveillance starting at age 30-35 years due to 30-60% lifetime risk of endometrial cancer 4

Special Considerations for Adolescents

• In adolescents, 95% of abnormal uterine bleeding is dysfunctional, though systematic evaluation is required to exclude underlying systemic or oncological diseases 2
• Use combined hormonal contraceptives as first-line for mild to moderate bleeding in adolescents, with progestin-only options as alternatives 2