Uterine rupture

Uterine rupture is a pregnancy complication that is life-threatening for the mother and the baby. It occurs in approximately one in every 4,000 births, and in most cases, during labor. This condition is caused by gross uterine distention or uterine scarring; patients who have had a C-section in a previous pregnancy are particularly prone to uterine rupture. Signs and symptoms may vary depending on the location and the extent of the rupture. A sudden pause in contractions takes place after rupture, along with an abnormal fetal heart rate (usually bradycardia), severe abdominal pain, vaginal bleeding, and hemodynamic instability. Women with this condition must undergo laparotomy and emergency C-section. If the uterus is severely damaged and cannot be repaired –or the bleeding does not cease– hysterectomy is necessary.

• Incidence: 1/4000 births ^[1][2]

Epidemiological data refers to the US, unless otherwise specified.

Uterine rupture is primarily caused by uterine distention. Theoretically, this can occur at any stage of pregnancy; however, it usually takes place during active labor because of the massive force exerted during contractions.

• Uterine distention
  • Delay in labor progression because of fetal malpresentation
  • Fetal macrosomia and multiple gestations
  • Overdose of oxytocin
• Uterine scar/prior uterine surgery (e.g., C-section or myomectomy)
• Traumatic rupture (e.g., iatrogenic or caused by an accident)
• Other risk factors ^[3]
  • Maternal age ≥ 35 years
  • Interdelivery interval < 16 months
  • Postterm pregnancy
  • Macrosomia
  • History of spontaneous abortion
  • Induction of labor

References:^[4][5][6]

• Uterine rupture: connection to the abdomen
• Uterine dehiscence (closed rupture): perforation covered by the visceral peritoneum

Imminent rupture

• Severe abdominal pain
• Increased contractions followed by hyperactive labor
• Bandl ring: muscular ring that can be seen above the belly button due to the powerful contractions of the upper uterine segment

Uterine rupture

• Severe abdominal pain
• Sudden pause in contractions
• Fetal distress (e.g., deteriorating fetal heart rate)
• Vaginal bleeding
• Hemodynamic instability (as a result of abdominal bleeding)
• Loss of fetal station
• Palpable fetal parts through the rupture

References:^{[4][5][7][8][9]}

• Uterine dehiscence
  • Closed rupture
  • Occurs mostly as a result of a scar rupture in the late months of pregnancy or when contractions begin
  • Most cases of uterine dehiscence are an incidental finding during repeat cesarean delivery.

See “Differential diagnosis of antepartum bleeding.”

The differential diagnoses listed here are not exhaustive.

• Imminent rupture
  • Immediate IV tocolysis
  • Emergency C-section
• Uterine rupture
  • Immediate laparotomy with emergency C‑section ^[5]
  • Hysterectomy necessary if the bleeding does not cease
• Uterine dehiscence: Cesarean delivery before labor begins is recommended to avoid a complete rupture.

• Traumatic and spontaneous ruptures increase the mortality rate of the mother and the baby.
• Open ruptures lead to hypovolemia and hypoxia; as a result, the fetal mortality rate is increased.