Author: Francesca Silvestri, MD

Editor: Brian Gilberti, MD

Definition

  • AUB (per ACOG): menstrual bleeding outside normal volume, duration, regularity, or frequency in a non-pregnant, reproductive-age patient.
  • Terminology: FIGO and ACOG have retired “menorrhagia,” “metrorrhagia,” and “dysfunctional uterine bleeding.” Use heavy menstrual bleeding (HMB) and intermenstrual bleeding (IMB).
  • Scope: this covers non-pregnant, reproductive-age patients. Bleeding more than 1 year after menopause is postmenopausal bleeding — endometrial cancer until proven otherwise — and follows a different pathway.

Epidemiology

  • AUB accounts for approximately one-third of outpatient gynecology visits.
  • In a single-year national estimate (2016 Nationwide Emergency Department Sample), there were ~1.03 million AUB-related ED visits, of which 11.2% resulted in inpatient admission.

Pathophysiology

  • Framework for etiology: PALM-COEIN (FIGO System 2, 2018 revision)
    • Structural (PALM): Polyps, Adenomyosis, Leiomyoma, Malignancy and hyperplasia
      • Cause bleeding through cavity distortion, increased endometrial surface area, and abnormal local vasculature; the dominant mechanism varies by lesion.
      • Leiomyomas = most common structural cause.
    • Ovulatory dysfunction (AUB-O) is the most common cause overall in reproductive-age patients, and anovulation accounts for roughly 90% of adolescent AUB. Fibroids are highly prevalent but frequently asymptomatic — prevalence is not causation.
    • Non-structural (COEIN): Coagulopathy, Ovulatory dysfunction, Endometrial, Iatrogenic, Not otherwise classified
      • Coagulopathy impairs endometrial hemostasis.
      • Ovulatory dysfunction → unopposed estrogen → irregular endometrial shedding.

Clinical Presentation

  • Spectrum from heavy-but-stable bleeding to frank shock.
  • Bleeding pattern: heavy/prolonged (most common), intermenstrual, or acute profuse hemorrhage.
  • Hemodynamic compromise: tachycardia, diaphoresis, pallor, orthostasis, AMS.
  • Associated symptoms: fatigue, dizziness, dyspnea on exertion (from anemia), syncope, pelvic pain, clot passage.

Evaluation

  • Pregnancy test first. AUB is by definition a diagnosis in the non-pregnant patient; a positive hCG moves the patient onto an entirely different algorithm (ectopic, miscarriage, GTD).
  • Immediate: ABCs, hemodynamic status, large-bore IV access, type & screen for any significant bleeding — not only for instability.
  • History: guided by PALM-COEIN; current bleeding episode, menstrual/sexual history, contraceptive/hormonal use, screen for bleeding disorders.
  • Exam: speculum exam to assess bleeding; bimanual exam for uterine size/tenderness.
  • Labs: pregnancy test, CBC w/ differentiation, coagulation studies (PT/INR, PTT, fibrinogen), type and screen, TSH (if ovulatory dysfunction suspected). Risk-stratify the coags — they are low-yield in a stable patient with no personal or family bleeding history.
  • Do not send von Willebrand studies from the ED. Acute-phase response, stress, and exogenous estrogen all raise vWF levels and produce false negatives. Screen with history (ISTH-BAT or equivalent) and refer for outpatient testing off hormonal therapy.
  • Imaging: TVUS preferred if structural etiology suspected.

Management

Hemodynamically unstable

  • Large-bore IV access, fluid resuscitation, prep for transfusion.
  • Activate MTP if signs of shock — trigger on physiology (persistent instability despite resuscitation, ongoing transfusion requirement, rapidly falling hemoglobin) rather than an estimated blood-loss volume. Visual estimation of vaginal blood loss is highly unreliable.
  • Intrauterine tamponade as a bridge:
    • 26F Foley (30 cc balloon) is the standard bridge in the non-gravid uterus — needs ≥1 cm cervical dilation to insert.
    • Bakri volumes of 200–500 cc are postpartum figures. The non-gravid cavity holds a small fraction of that — inflate to resistance and tamponade effect, not to a postpartum target.
    • Jada device (suction-based) — FDA-cleared for postpartum hemorrhage only; use in the non-gravid uterus is off-label with no supporting data and needs 2–3 cm cervical dilation.
    • If large transfusion requirement → consider exam under anesthesia with GYN for tamponade placement.
    • Can perform bedside TVUS to assess etiology of hemorrhage.
  • IV TXA 10 mg/kg (max 600 mg/dose) q8h — the ACOG-aligned dose for acute AUB. The 1 g/redose-at-1-hour regimen is trauma and postpartum hemorrhage dosing (CRASH-2, WOMAN); do not quote it for AUB without labeling it an extrapolation.
  • IV conjugated equine estrogen (CEE, Premarin) 25 mg q4–6h for up to 24 h — consider if endometrium thin; avoid with prior VTE, migraine w/aura, cardiac history, age >35 + smoker, elevated malignancy risk.
    • Evidence rests on a single small RCT, and many ED pharmacies do not stock it. Have a backup ready: high-dose oral estrogen or a progestin regimen plus TXA.
  • If tamponade fails → surgical management (D&C w/hysteroscopy, uterine artery embolization, hysterectomy).
  • If GYN available, consult and co-manage with GYN early, or stabilize and transfer to a center with GYN and/or IR capabilities.

Hemodynamically stable

Medical management first-line

  • IV conjugated equine estrogen 25 mg q4–6h (same caveats as above).
  • Monophasic combined OCP taper — 30–35 mcg ethinyl estradiol, 1 tab TID x 7 days (or TID until bleeding stops, then BID x 2 days, then daily); effect usually seen in 6–12 hours. Co-prescribe an antiemetic — high-dose estrogen nausea is the main reason patients abandon the regimen.
  • Do not combine a combined hormonal contraceptive with tranexamic acid. Concomitant use is a labeled contraindication (Lysteda, Section 4) because of additive thrombotic risk; patients on hormonal contraception were excluded from the trials supporting oral TXA. Pick one.
  • Oral medroxyprogesterone acetate — 20 mg PO TID x 7 days (ACOG CO 557); the preferred hormonal option when estrogen is contraindicated; nausea is the most common side effect.
  • Oral TXA 1.3 g TID x 5 days — good for heavy, regular, discrete periods; max 5-day course; do not co-prescribe with a combined OCP (see above).
  • Nexplanon-related bleeding: high-dose NSAID (ibuprofen 400 mg TID x 5–7 days).

Surgical options

Medical management fails/contraindicated

  • D&C w/hysteroscopy — used in suspected structural pathology.
  • Uterine artery embolization — fertility-preserving, good for discrete fibroid pathology or prior transfusion history.
  • Endometrial ablation — only if fertility not desired and malignancy excluded.
  • Hysterectomy — definitive treatment for refractory bleeding.

Complications/Special Considerations

  • Hemorrhagic shock and DIC can develop with significant ongoing blood loss.
  • AUB = most common cause of iron deficiency anemia in premenopausal patients.
  • Up to 20% of patients with AUB have an underlying bleeding disorder (vWD most common) — avoid NSAIDs in this group.
  • Adolescents: ovulatory dysfunction predominates over structural causes.
  • Anticoagulated patients are a distinct pathway. DOACs and warfarin substantially worsen AUB and account for a growing share of ED presentations. Avoid high-dose NSAIDs. Favor non-hormonal control (TXA, provided the indication for anticoagulation does not itself contraindicate it) and progestin-only regimens over estrogen. Reverse or hold anticoagulation only for life-threatening bleeding and in co-management with GYN and hematology — do not manage this as routine AUB.
  • Keep fertility preservation in mind when selecting management.

ED Disposition

  • Admit/GYN OR: persistent instability despite resuscitation, ongoing brisk bleeding, transfusion requirement, failed medical management or failed tamponade, DIC, or need for procedural intervention.
  • Discharge candidates: hemodynamically stable, bleeding controlled or clearly slowing after ED therapy, tolerating PO, negative hCG, no orthostasis, and confirmed GYN follow-up within 24–72 hours.
  • There is no single hemoglobin cutoff. Anchor on symptoms, trajectory, and follow-up reliability rather than a number — a stable patient at 7.5 g/dL with confirmed follow-up may go home, while a symptomatic patient at 9 g/dL who is still bleeding briskly may not.
  • Social factors are legitimate admission criteria: distance from care, ability to fill and afford the prescription (including the antiemetic), and reliable follow-up.

Next Steps

  • Early GYN consultation for any hemodynamically unstable AUB or when medical management fails.
  • Outpatient follow-up for TVUS/further workup if not obtained in the ED.
  • Iron studies and consideration of iron repletion for patients with anemia.
  • Referral for hematology workup if bleeding disorder suspected.
  • Name the 52 mg levonorgestrel IUD in the discharge conversation. Once acute bleeding is controlled and malignancy excluded, it is the most effective maintenance option for heavy menstrual bleeding (71–95% reduction in blood loss).

Take-Home Points

  • Use PALM-COEIN as your DDx for AUB in non-pregnant, reproductive-age patients.
  • Stable patients: medical management first — OCP taper, oral TXA, oral progestin, high-dose NSAID, or IV estrogen — but never an OCP and TXA together.
  • Unstable patients: ABCs, transfuse as needed, IV TXA (10 mg/kg, max 600 mg/dose) as a temporizing measure, early GYN involvement for tamponade vs. surgical management.
  • Disposition: stability, bleeding trajectory, PO tolerance, and confirmed GYN follow-up — not a hemoglobin number.

References

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