- Pathophysiology/Etiology
- Full-thickness disruption of the uterine wall (endometrium, myometrium, and perimetrium). A tear in the uterine wall, often occurring during labor.
- Highest risk factor: Prior uterine surgery, especially a classical (vertical) cesarean section scar.
- Other risk factors: Trial of labor after cesarean (TOLAC), myomectomy, uterine overdistension (multiple gestations, polyhydramnios), labor induction (especially with prostaglandins/oxytocin), obstructed labor, and trauma.
- Clinical Presentation
- Most common sign: Sudden onset of fetal distress (e.g., severe bradycardia, prolonged decelerations) on fetal heart monitoring.
- Sudden, severe abdominal pain that may persist between contractions.
- Cessation of uterine contractions.
- Loss of fetal station (recession of the presenting part).
- Vaginal bleeding (can be intra-abdominal and not apparent externally).
- Maternal hemodynamic instability (hypotension, tachycardia) due to hemorrhage.
- Diagnosis
- Primarily a clinical diagnosis requiring a high index of suspicion, especially in a patient with a prior C-section undergoing labor.
- Diagnosis is confirmed by direct visualization during emergency laparotomy.
- Imaging is generally not appropriate due to the need for immediate intervention.
- DDx (Differential Diagnosis)
- Placental abruption: Painful vaginal bleeding, uterine hypertonicity/tenderness. Fetus is still contained within the uterus.
- Placenta previa: Painless vaginal bleeding.
- Uterine dehiscence: Incomplete rupture where the uterine serosa remains intact. Often asymptomatic and less catastrophic than a full rupture.
- Management/Treatment
- Immediate emergency laparotomy and cesarean delivery to deliver the fetus and control hemorrhage.
- Maternal resuscitation is critical: place two large-bore IVs, administer IV fluids, and transfuse blood products as needed.
- After delivery, the uterus may be repaired if the rupture is small and the patient is stable and desires future fertility.
- Hysterectomy is often necessary for large, complex ruptures or if hemorrhage cannot be controlled.
- Key Associations/Complications
- Maternal: Severe hemorrhage, hypovolemic shock, bladder injury, need for hysterectomy (loss of fertility), and rarely, death.
- Fetal: High risk of fetal hypoxia/anoxia leading to brain injury or death if delivery is not accomplished within minutes (typically 10-40 minutes).
- Buzzwords: “Loss of fetal station,” “sudden fetal bradycardia in patient with prior C-section,” “cessation of contractions.”