Reproductive · PANCE / PANRE

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

CategoryCauseHallmark
P (structural)PolypIntermenstrual bleeding; SIS/hysteroscopy
A (structural)AdenomyosisHeavy painful menses; boggy uterus; MRI
L (structural)LeiomyomaHeavy menses, bulk symptoms; TVUS
M (structural)Malignancy / hyperplasiaPostmenopausal or risk-factor bleeding; biopsy
C (nonstructural)CoagulopathyHeavy menses since menarche; vWF panel
O (nonstructural)Ovulatory dysfunctionIrregular cycles; PCOS, thyroid, prolactin
E (nonstructural)EndometrialPrimary endometrial hemostasis disorder
I (nonstructural)IatrogenicHormones, anticoagulants, IUDs
N (nonstructural)Not otherwise classifiedAVMs, cesarean scar, other rare causes
FIGO PALM-COEIN classification of abnormal uterine bleeding.

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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