Abnormal Uterine Bleeding
Bleeding outside normal volume, regularity, frequency, or duration — classified by PALM-COEIN.
Also known as: AUB, menorrhagia, metrorrhagia, menometrorrhagia, dysfunctional uterine bleeding, heavy menstrual bleeding
Overview
Bleeding from the uterine corpus that is abnormal in volume, regularity, frequency, or duration occurring in the absence of pregnancy. The PALM-COEIN classification (FIGO 2011) divides causes into structural (Polyp, Adenomyosis, Leiomyoma, Malignancy/hyperplasia) and nonstructural (Coagulopathy, Ovulatory dysfunction, Endometrial, Iatrogenic, Not otherwise classified).
Epidemiology
Affects 10-30% of reproductive-age women; common cause of outpatient gynecology visits and accounts for ~20% of hysterectomies.
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Risk factors
- Anovulation (extremes of reproductive age — adolescence, perimenopause; PCOS)
- Obesity (peripheral conversion of androgens to estrogen)
- Coagulation disorders (von Willebrand disease most common in adolescents with heavy menses)
- Anticoagulant therapy
- Endometrial hyperplasia/cancer risk: age >45, unopposed estrogen, tamoxifen, Lynch syndrome
- IUDs and hormonal contraception (iatrogenic spotting)
Pathophysiology
Structural causes distort or replace endometrium (polyps, fibroids, malignancy). Anovulation removes the cyclic progesterone-driven decidualization that normally produces orderly shedding, leaving disorganized estrogen-stimulated endometrium prone to breakthrough bleeding. Coagulopathies impair primary hemostasis at the endometrial level.
Clinical presentation
Symptoms
- Heavy menstrual bleeding (>80 mL/cycle, >7 days, or self-reported impact on QOL)
- Intermenstrual bleeding (between predictable menses)
- Postcoital bleeding (think cervical pathology)
- Irregular cycles (<21 or >35 days, or variable >7-9 days cycle-to-cycle)
- Postmenopausal bleeding — always abnormal until proven otherwise
Signs / physical exam
- Pallor, tachycardia, orthostasis in acute heavy bleeding
- Enlarged or irregular uterus (fibroids, adenomyosis)
- Cervical lesion or polyp on speculum exam
- Signs of androgen excess (PCOS), galactorrhea (prolactinoma), thyromegaly
Differential diagnosis
- Pregnancy-related bleeding (threatened/spontaneous abortion, ectopic, GTD) — Always check hCG first
- Cervical pathology (polyp, cervicitis, malignancy) — Speculum exam, Pap testing, cervical biopsy
- Vaginal/vulvar source — Atrophy, trauma, foreign body, malignancy
- Urinary or GI source — Hematuria, hematochezia masquerading as vaginal bleeding
- Endometrial hyperplasia or carcinoma — Postmenopausal bleeding or any AUB with risk factors → endometrial biopsy
- Coagulopathy (von Willebrand, platelet dysfunction) — Heavy menses since menarche, easy bruising, family history
- Thyroid dysfunction or hyperprolactinemia — Menstrual irregularity; check TSH, prolactin
Diagnostic workup
Labs
- Urine or serum hCG — first test in any reproductive-age woman
- CBC, ferritin
- TSH, prolactin
- Coagulation studies (PT/PTT, vWF panel) if heavy bleeding since menarche or family history
- GC/CT testing in at-risk patients
Imaging
- Transvaginal ultrasound — first-line for structural assessment
- Saline-infusion sonohysterography or hysteroscopy — for suspected intracavitary lesions
- Endometrial biopsy indicated for: age ≥45 with AUB, age <45 with risk factors (obesity, chronic anovulation, tamoxifen, Lynch syndrome, unopposed estrogen), any postmenopausal bleeding, or persistent AUB despite medical therapy
Diagnostic algorithm
| Category | Cause | Hallmark |
|---|---|---|
| P (structural) | Polyp | Intermenstrual bleeding; SIS/hysteroscopy |
| A (structural) | Adenomyosis | Heavy painful menses; boggy uterus; MRI |
| L (structural) | Leiomyoma | Heavy menses, bulk symptoms; TVUS |
| M (structural) | Malignancy / hyperplasia | Postmenopausal or risk-factor bleeding; biopsy |
| C (nonstructural) | Coagulopathy | Heavy menses since menarche; vWF panel |
| O (nonstructural) | Ovulatory dysfunction | Irregular cycles; PCOS, thyroid, prolactin |
| E (nonstructural) | Endometrial | Primary endometrial hemostasis disorder |
| I (nonstructural) | Iatrogenic | Hormones, anticoagulants, IUDs |
| N (nonstructural) | Not otherwise classified | AVMs, cesarean scar, other rare causes |
Treatment
First-line
- Address structural cause if identified (polypectomy, myomectomy, etc.)
- Nonhormonal: NSAIDs (mefenamic acid, ibuprofen, naproxen) — reduce flow ~20-50%
- Tranexamic acid 1.3 g TID × up to 5 days per cycle — reduces flow ~40-60%
- Hormonal: combined OCP, progestin-only pills, levonorgestrel IUD (most effective medical option), depot medroxyprogesterone
Acute heavy bleeding (hemodynamically stable)
- High-dose IV conjugated estrogen 25 mg q4-6h
- Or high-dose oral COCP taper (e.g., one pill TID × 7 days then taper)
- Or oral medroxyprogesterone 20 mg TID × 7 days then taper
- Tranexamic acid as adjunct
Acute heavy bleeding (hemodynamically unstable)
- ABCs, IV access, fluids, transfusion as needed
- IV conjugated estrogen
- Intrauterine tamponade with Foley balloon, D&C if medical therapy fails
- Uterine artery embolization or hysterectomy as last resort
Surgical (refractory)
- Endometrial ablation — appropriate only if childbearing complete; not for hyperplasia/cancer
- Hysterectomy — definitive
Complications
- Iron-deficiency anemia
- Missed diagnosis of endometrial hyperplasia or cancer
- Impaired quality of life, work absenteeism
- Hemodynamic instability in acute hemorrhage
PANCE pearls
- Any postmenopausal bleeding requires evaluation for endometrial cancer (endometrial biopsy or TVUS — endometrial thickness >4 mm warrants biopsy).
- The levonorgestrel-releasing IUD reduces menstrual blood loss by ~80-90% and is the most effective medical therapy for AUB without structural pathology.
- Endometrial ablation does not provide contraception and is contraindicated in women desiring future fertility.
- Adolescents with heavy menses at menarche should be screened for von Willebrand disease.
- Tamoxifen causes endometrial proliferation, polyps, and increases endometrial cancer risk — any bleeding warrants biopsy.
References
- ACOG PB 128 — ACOG Practice Bulletin No. 128: Diagnosis of Abnormal Uterine Bleeding in Reproductive-Aged Women
- ACOG PB 557 — ACOG Committee Opinion 557: Management of Acute Abnormal Uterine Bleeding in Nonpregnant Reproductive-Aged Women
- FIGO PALM-COEIN — FIGO Classification System for Causes of Abnormal Uterine Bleeding (Munro et al., Int J Gynaecol Obstet 2011)
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