Harvey's Garden

Uterine atony

Properties2
tags—
aliases

3 min read

Epidemiology & Risk Factors

  • Most common cause of primary postpartum hemorrhage (PPH) (>80% of cases).
  • Uterine overdistension:
    • Multifetal gestation.
    • Polyhydramnios.
    • Fetal macrosomia.
  • Uterine muscle fatigue:
    • Prolonged or precipitous labor.
    • High parity.
    • High-dose or prolonged oxytocin administration.
  • Uterine infection: Intra-amniotic infection (chorioamnionitis).
  • Uterine relaxants:
    • Halogenated general anesthetics.
    • High-dose IV magnesium sulfate.
  • Prior history of PPH.

Clinical Features

  • Excessive vaginal bleeding within 24h of delivery (>500 mL after vaginal delivery, >1000 mL after C-section).
  • Physical Exam:
    • Soft, boggy (“squishy”), enlarged uterus on palpation.
    • Uterine fundus located above the umbilicus.
  • Systemic signs: Tachycardia, hypotension, pale/diaphoretic skin (hypovolemic shock if unmanaged).

Diagnosis

  • Clinical Diagnosis: Identified primarily by clinical presentation and physical exam finding of a soft, boggy, enlarged uterus during active postpartum bleeding.
  • Initial Bedside Step: Bimanual exam to evaluate uterine tone and clear intra-cervical/vaginal clots.
  • Key Imaging:
    • Transabdominal/Transvaginal US: Indicated if uterus remains boggy or bleeding persists despite initial interventions to rule out retained products of conception (RPOC) or uterine rupture.
  • Key Labs: CBC (Hb/Hct), Type & Crossmatch, PT/INR, PTT, Fibrinogen (to monitor for DIC).

Differential Diagnostics

  • Retained Products of Conception (RPOC):
    • Differentiating feature: Firm or poorly contracted uterus, missing placental cotyledon, echogenic mass with vascular flow on bedside US.
  • Genital Tract Lacerations:
    • Differentiating feature: Firm, well-contracted uterus with persistent bright red vaginal bleeding; lacerations visualized on speculum exam.
  • Uterine Inversion:
    • Differentiating feature: Absent fundus on abdominal palpation, smooth round mass visible at or prolapsed past the vaginal introitus, severe pain, severe neurogenic shock.
  • Uterine Rupture:
    • Differentiating feature: Sudden abdominal pain, loss of fetal station intrapartum, abdominal rigidity, intraperitoneal hemorrhage.
  • Coagulopathy / DIC:
    • Differentiating feature: Oozing from IV line sites, petechiae, decreased platelets, low fibrinogen, prolonged PT/PTT.

Management

  1. Emergency Stabilization & Initial Resuscitation:
    • ABCs: Two large-bore IVs (16-18 gauge), IV crystalloid boluses, blood products (pRBCs, FFP, platelets) as needed.
    • Continuous monitoring of vitals and urine output (Foley catheter to empty bladder, which facilitates uterine contraction).
  2. First-Line Medical & Physical Therapy:
    • Bimanual uterine massage (simultaneously compresses uterus and stimulates contraction).
    • IV Oxytocin infusion (1st-line uterotonic agent).
  3. Second-Line Uterotonic Agents (if oxytocin + massage fails):
    • Methylergonovine (IM): Smooth muscle constriction.
      • Contraindication: Hypertension / Preeclampsia (causes severe hypertensive crisis). c
    • Carboprost (PGF2α) (IM or intra-myometrial): Prostaglandin analog.
      • Contraindication: Asthma (causes severe bronchospasm).
    • Misoprostol (PGE1) (Sublingual or PR): Rapid absorption, safe in HTN and asthma.
    • Tranexamic Acid (TXA) (IV): Antifibrinolytic; administer within 3h of bleeding onset.
  4. Refractory / Interventional Measures:
    • Intrauterine balloon tamponade (e.g., Bakri balloon) to compress bleeding endo-myometrial vessels.
    • Uterine artery embolization (UAE): Option only if pt is hemodynamically stable and IR is immediately available.
  5. Surgical Interventions (if unstable or refractory to non-surgical measures):
    • Uterine compression sutures (e.g., B-Lynch suture).
    • Ligation of uterine or internal iliac (hypogastric) arteries.
    • Hysterectomy: Definitive, last-resort intervention for life-threatening hemorrhage.

Complications

  • Hypovolemic shock and multiorgan failure.
  • Disseminated Intravascular Coagulopathy (DIC).
  • Sheehan Syndrome: Ischemic necrosis of the anterior pituitary gland secondary to severe hypovolemic shock (presents as failure to lactate, amenorrhea, secondary hypothyroidism/adrenal insufficiency).
  • Asherman Syndrome: Intrauterine adhesions (if aggressive curettage performed).
  • Permanent loss of fertility (if emergency hysterectomy is performed).

Graph View

Backlinks