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 4000 births and, in most cases, during labor. This condition is caused by gross uterine distention or uterine scarring; patients who have had a cesarean delivery 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 cesarean delivery. If the uterus is severely damaged and cannot be repaired, or the bleeding is refractory, 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. ^[3][4][5]

• 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., cesarean delivery or myomectomy)
• Traumatic rupture (e.g., iatrogenic or caused by an accident)
• Other risk factors ^[6]
  • Maternal age ≥ 35 years
  • Interdelivery interval < 16 months
  • Postterm pregnancy
  • Macrosomia
  • History of spontaneous abortion
  • Induction of labor

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

Signs of imminent uterine rupture ^[7]

• 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

Signs of uterine rupture ^[3][7][8][9]

• Fetal distress (earliest and most sensitive sign)
• Severe abdominal pain
• Referred pain in the shoulder may be present.
• Sudden pause in contractions
• Light to moderate vaginal bleeding
• Hemodynamic instability (as a result of abdominal bleeding)
• Loss of fetal station (a specific but uncommon sign)
• Palpable fetal parts through the rupture (a specific but uncommon sign)

Uterine rupture generally occurs during active labor. However, a third of uterine ruptures occur prior to the onset of labor. ^[8][10]

• Uterine rupture is clinical diagnosis based on signs of imminent uterine rupture and other signs of uterine rupture. ^[8]
  • Evaluate patients immediately if there are signs of fetal distress.
  • Pain or vaginal bleeding are unreliable signs and may be absent.
• Obtain emergency preoperative diagnostics.
• Consider bedside ultrasound if it does not delay treatment. Supportive findings include: ^[11]
  • Hemoperitoneum (positive FAST)
  • Protrusion of amniotic sac
  • Endometrial or myometrial defect
  • Extrauterine hematoma

If clinical suspicion is high, do not delay emergency cesarean delivery for confirmatory imaging. ^[8][10]

See “Differential diagnosis of antepartum bleeding.”

The differential diagnoses listed here are not exhaustive.

• ABCDE approach and immediate hemodynamic support
• Immediate OB-GYN consultation for emergency cesarean delivery ^[8][12]
• Management of hemorrhagic shock and massive transfusion as needed
• Avoid uterotonic agents. ^[8]
• If signs of imminent uterine rupture are present: Consider IV tocolytics in consultation with OB-GYN as a temporizing measure.
• Consider hysterectomy for refractory hemorrhage.
• Urgently consult neonatology for possible neonatal resuscitation.

All patients with uterine rupture or imminent rupture require immediate laparotomy with emergency cesarean delivery within 30 minutes. ^[8]

• 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.

Uterine dehiscence

• Separation of a uterine scar without rupture of the serosa
• Occurs mostly in the late months of pregnancy or when contractions begin
• Most cases of uterine dehiscence are incidentally found during repeat cesarean delivery.
• Management: Cesarean delivery before labor begins is recommended to avoid a complete rupture.