Definition

• Common U.S. definition: cumulative blood loss at least 1,000 mL, or any blood loss with signs or symptoms of hypovolemia, within 24 hours after birth.
• Primary PPH: within 24 hours of birth.
• Secondary PPH: after 24 hours to 6 weeks postpartum.
  Barash, Cullen, and Stoelting’s Clinical Anesthesia, 9e, p. 1968; Tintinalli's Emergency Medicine, p. 2129.

Causes: the “4 Ts”

1. Tone - uterine atony, the most common cause
2. Trauma - cervical, vaginal, perineal laceration; uterine rupture or inversion
3. Tissue - retained placental tissue, placenta accreta spectrum
4. Thrombin - inherited or acquired coagulation disorder

Immediate management in hospital

• Call for senior obstetric, anesthesia, blood-bank, and operating-room support.
• Quantify blood loss; monitor pulse, blood pressure, oxygen saturation, urine output, and mental status.
• Establish two large-bore IV lines, send CBC, coagulation studies, fibrinogen, and crossmatch blood.
• Begin warmed IV fluid resuscitation and early blood-product replacement when indicated.
• Identify and correct the cause using the 4 Ts.
• If the uterus is boggy, perform uterine massage and give uterotonics, usually oxytocin first.
• Give tranexamic acid early, ideally within 3 hours of birth, for clinically diagnosed PPH unless contraindicated.
• Inspect and repair genital-tract tears; remove retained tissue if present; promptly correct uterine inversion.
• Escalate uncontrolled bleeding to uterine balloon tamponade, uterine compression sutures, arterial embolization where available, vascular ligation, or hysterectomy.

• Massage uterus
• Oxytocic drugs
• Tranexamic acid
• IV fluids
• Vaginal/genital tract examination
• Escalation of care

Important uterotonic cautions

• Oxytocin: first-line for atony.
• Methylergometrine/ergometrine: avoid in hypertension or preeclampsia.
• Carboprost: avoid or use extreme caution in asthma and significant cardiovascular disease.
• Misoprostol: an alternative or adjunct where appropriate.

Prevention

• Active management of the third stage of labor, particularly prophylactic uterotonic administration, reduces risk.
• Antenatally identify anemia, placenta previa/accreta risk, prior PPH, multiple gestation, prolonged labor, chorioamnionitis, uterine overdistension, and coagulation disorders.
• Prepare a delivery and transfusion plan for high-risk patients.