Uterine rupture

Uterine rupture is a potentially catastrophic event during childbirth by which the integrity of the myometrial wall is breached. In an incomplete rupture the peritoneum is still intact. With a complete rupture the contents of the uterus may spill into the peritoneal cavity or the broad ligament. A uterine rupture is a life-threatening event for mother and baby.

A uterine rupture typically occurs during active labor, but may already develop during late pregnancy.

Uterine dehiscence is a similar condition, but involves fewer layers, less bleeding, and less risk.^[1]

Risk factors and causes

A uterine scar from a previous cesarean section is the most common risk factor. (In one review, 52% had previous cesarean scars.)^[2] Other forms of uterine surgery that result in full-thickness incisions (such as a myomectomy), dysfunctional labor, labor augmentation by oxytocin or prostaglandins, and high parity may also set the stage for uterine rupture. In 2006, an extremely rare case of uterine rupture in a first pregnancy with no risk factors was reported.^[3]

Presentation

Symptoms of a rupture may be initially quite subtle. An old cesarean scar may undergo dehiscence; but with further labor the woman may experience abdominal pain and vaginal bleeding, though these signs are difficult to distinguish from normal labor. Often a deterioration of the fetal heart rate is a leading sign, but the cardinal sign of uterine rupture is loss of fetal station on manual vaginal exam. Intra-abdominal bleeding can lead to hypovolemic shock and death. Although the associated maternal mortality is now less than one percent, the fetal mortality rate is between two and six percent when rupture occurs in the hospital.

In pregnancy uterine rupture may cause a viable abdominal pregnancy. This is what accounts for most abdominal pregnancy births.

Treatment

Emergency exploratory laparotomy with cesarean delivery accompanied by fluid and blood transfusion are indicated for the management of uterine rupture. Depending on the nature of the rupture and the condition of the patient, the uterus may be either repaired or removed (cesarean hysterectomy). Delay in management places both mother and child at significant risk.

Signs and symptoms

• Abdominal pain and tenderness. The pain may not be severe; it may occur suddenly at the peak of a contraction. The woman may describe a feeling that something "gave way" or "ripped."
• Chest pain, pain between the scapulae, or pain on inspiration—Pain occurs because of the irritation of blood below the woman's diphragm
• Hypovolemic shock caused by hemorrhage—Falling blood pressure, tachycardia, tachypnea, pallor, cool and clammy skin, and anxiety. The fall in blood pressure is often a late sign of hemorrhage
• Signs associated with fetal oxygenation, such as late decelerations, reduced variability, tachycardia, and bradycardia
• Absent fetal heart sounds with a large disruption of the placenta; absent fetal heart activity by ultrasound examination
• Cessation of uterine contractions
• Palpation of the fetus outside the uterus (usually occurs only with a large, complete rupture). The fetus is likely to be dead at this point.
• Signs of an abdominal pregnancy

See also

• Uterine perforation

References