Postpartum hemorrhage

Epidemiology & Risk Factors

• Definition: Cumulative blood loss $\ge$ 1,000 mL OR blood loss accompanied by signs/symptoms of hypovolemia within 24 hr of delivery (primary PPH).
• Mnemonic: The 4 T’s:
  • Tone (Uterine Atony): Most common cause (~70-80%).
    • Overdistension: Multiple gestation, polyhydramnios, macrosomia.
    • Uterine fatigue: Prolonged labor, rapid/precipitous labor, high multiparity.
    • Infection: Chorioamnionitis.
    • Medications: Halogenated anesthetics, high-dose tocolytics, prolonged oxytocin use (receptor desensitization).
  • Trauma (Lacerations, Rupture, Inversion) (~20%):
    • Operative vaginal delivery (forceps, vacuum), episiotomy, macrosomia.
    • Prior uterine surgery (C-section, myomectomy) $\to$ risk for uterine rupture.
    • Excessive umbilical cord traction $\to$ risk for uterine inversion.
  • Tissue (Retained Products of Conception [POC]) (~10%):
    • Retained placenta, succenturiate lobe, prior uterine curettage.
    • Placenta accreta spectrum (increta, percreta), placenta previa.
  • Thrombin (Coagulopathies) (<1%):
    • Inherited: von Willebrand disease (vWD), hemophilia carriers.
    • Acquired: DIC (associated with abruptio placentae, severe preeclampsia, HELLP syndrome, amniotic fluid embolism), therapeutic anticoagulation.

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Clinical Features

• History & Vitals:
  • Continuous, heavy vaginal bleeding (>1 soaked peripad/hr).
  • Tachycardia, hypotension, tachypnea (late findings due to pregnancy-induced expanded blood volume).
  • Altered mental status, lightheadedness, syncope.
• Physical Exam:
  • Uterine Atony: Uterus is boggy, soft, poorly contracted, and enlarged above the umbilicus.
  • Genital Tract Laceration: Uterus is firm and well-contracted, but ongoing bright red vaginal bleeding persists.
  • Retained Tissue: Incomplete placenta on inspection; firm or mildly boggy uterus with persistent bleeding.
  • Uterine Inversion: Smooth, round mass protruding through cervix/introitus; uterine fundus not palpable abdominally; severe neurogenic/hypovolemic shock.
  • Uterine Rupture: Severe, sudden abdominal pain; fetal bradycardia/recession of presenting part (intrapartum); severe postpartum hematoma/peritoneal signs (postpartum).
  • Hematoma (Vaginal/Retroperitoneal): Severe pelvic/rectal pain, tenesmus, hemodynamic instability with minimal visible external bleeding.

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Diagnosis

• Initial/Screening:
  • Clinical assessment: Bimanual uterine palpation + visual inspection of perineum, vagina, and cervix under adequate lighting.
  • Quantitative blood loss (QBL) measurement (drapes, gravimetric pad weighing).
• Key Labs:
  • Type & Crossmatch: Prepare $\ge$ 2-4 units PRBCs immediately.
  • CBC: Serial Hb/Hct (lag behind acute bleeding; do not wait to treat).
  • Coagulation Studies: PT/INR, aPTT, platelets.
  • Fibrinogen: Critical marker; fibrinogen < 200 mg/dL is highly predictive of severe PPH, active consumption, and impending DIC.
• Imaging:
  • Bedside Transabdominal / Transvaginal US:
    • Evaluates for retained POC (echogenic, vascular mass in endometrial cavity).
    • Excludes hemoperitoneum or retroperitoneal hematoma.

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Differential Diagnostics

• Uterine Atony vs Genital Laceration:
  • Diff by fundal exam: Atony presents with a soft, boggy uterus; lacerations present with a firm, well-contracted uterus with active bleeding.
• Retained POC vs Uterine Atony:
  • Diff by placental inspection (missing cotyledon) and pelvic US showing an echogenic endometrial mass; both can cause secondary atony.
• Uterine Inversion vs Vaginal Vault Hematoma:
  • Diff by physical exam: Inversion shows an absent fundus on abdominal palpation and an inverted uterine fundus at/through the introitus; hematoma presents as a tense, violaceous, highly painful mass in the vaginal wall with a normally situated fundus.
• Uterine Rupture vs Placental Abruption:
  • Diff by history and presentation: Rupture typically occurs in pts with prior uterine scars and features loss of station, sudden focal peritonitis, and retroperitoneal shock; abruption features uterine hypertonicity/tetany, painful dark red bleeding, and coagulopathy before delivery.
• Disseminated Intravascular Coagulation (DIC) vs Local PPH:
  • Diff by systemic bleeding: DIC presents with oozing from venipuncture/IV sites, surgical incisions, hematuria, accompanied by profound thrombocytopenia, elevated PT/PTT, and fibrinogen < 200 mg/dL.

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Management

• Immediate Resuscitation (ABCDE Approach):
  • Call for rapid response / obstetric hemorrhage team.
  • Two large-bore IVs (16-18 gauge).
  • Aggressive warmed crystalloid infusion (limit excessive crystalloid to prevent dilutional coagulopathy).
  • Empty the bladder via Foley catheter (a full bladder displaces the uterus and impedes contraction).
  • Massive Transfusion Protocol (MTP): If bleeding is persistent/unstable, infuse PRBCs, FFP, and Platelets in a 1:1:1 ratio.
  • Tranexamic Acid (TXA): Administer IV within 3 hr of delivery to decrease mortality. c
• Etiology-Specific Interventions:
  • Uterine Atony:
    • First-line Physical: Bimanual uterine massage.
    • Medical (Uterotonics):
      1. Oxytocin (IV infusion): First-line agent.
      2. Methylergonovine (Methergine; IM): Induces myometrial tetany. Contraindicated in HTN / Preeclampsia (causes vasoconstriction).
      3. Carboprost tromethamine (PGF2$\alpha$; IM): Contraindicated in Asthma (causes bronchospasm).
      4. Misoprostol (PGE1; SL/PR/PO): Safe in asthma and HTN; alternative or adjunct.
    • Second-line (Mechanical / Tamponade):
      • Intrauterine balloon tamponade (e.g., Bakri balloon) if uterotonics fail.
    • Third-line (Surgical / IR):
      • Uterine artery embolization (UAE) if hemodynamically stable.
      • Laparotomy with uterine compression sutures (B-Lynch).
      • Uterine artery ligation or internal iliac (hypogastric) artery ligation.
      • Emergent Hysterectomy: Definitive, life-saving measure when conservative/surgical measures fail.
  • Genital Tract Trauma:
    • Immediate surgical repair of cervical/vaginal lacerations under adequate anesthesia.
    • Hematomas < 5 cm: Observation, ice packs, pain control.
    • Expanding/large hematomas: Surgical incision, evacuation, and vessel ligation.
  • Uterine Inversion:
    • Immediate manual replacement of the fundus (Johnson maneuver) before the cervical ring contracts.
    • Discontinue uterotonics during replacement attempt.
    • If uterus is tightly contracted: Administer uterine relaxants (e.g., terbutaline, nitroglycerin, or inhaled anesthetics) $\to$ replace fundus $\to$ then administer uterotonics to prevent re-inversion.
    • Do not attempt to remove the placenta prior to uterine replacement (exacerbates hemorrhage).
  • Retained Tissue:
    • Manual extraction using sterile gauze.
    • Refractory: Ultrasound-guided suction curettage.