A separation of the uterine wall from the surrounding outer layers, or a tear through the layer or layers of the uterus is considered a uterine rupture. During a complete uterine rupture, when all the layers are compromised, the contents of the uterus may spill into the surrounding abdominal cavity. Uterine rupture is one of the most serious and possibly deadly complications that can occur during pregnancy. Fetal death rates are extremely high, and extreme illness or death very often occurs to the mother as well. Uterine rupture is extremely rare, and happens at a rate of less than 0.08 percent of all pregnancies.
The symptoms of uterine rupture are not unique to the condition. A prompt and accurate diagnosis is essential, as “only 10-37 minutes are available before clinically significant fetal morbidity becomes inevitable.” During uterine rupture, the fetus is at risk for severe bleeding and/or severe oxygen deprivation. Because most cases of uterine rupture occur during labor and delivery, the first sign of a problem may be irregularities in the fetus’s heart rate that would indicate fetal distress. Symptoms in the pregnant woman may include:
- Abdominal pain or tenderness
- Acute pain between contractions in labor
- Heavy bleeding
- Weak contractions, diminished force of contractions, and/or lengthening of pauses between contractions
- Fetus receding back up the birth canal
- Loss of muscle tone around the uterus
- A lump in the abdominal cavity where the placenta or fetus’s body has stuck through the uterus
- Shock (from internal hemorrhaging)
Sometimes, no symptoms are evident during uterine rupture or are indistinguishable from regular symptoms of labor or other obstetrical problems, such as placental abruption (premature separation of the placenta from the uterine wall).
There is no way to diagnose uterine rupture before it actually happens, nor is it predictable. For women with uterine scarring from a cesarean section, an ultrasound imaging exam can determine whether there are flaws in the scar. In addition, there are pre-existing conditions for which uterine rupture is more frequent. Spontaneous uterine rupture is extremely rare (less than 0.012 percent ), but a higher risk for uterine rupture exists if a woman has:
- A uterine scar from a previous surgery, including cesarean delivery, or another injury or trauma (90 percent of cases of uterine rupture are attributed to this cause).
- Had many previous births (the more previous births, the higher the risk), especially with deliveries via cesarean section.
- Labor induced or augmented with drugs such as oxytocin or prostaglandins.
- Been abusing cocaine, especially during pregnancy.
- Cancer of the uterus.
- A distended uterus (from too much amniotic fluid or multiple fetus).
- An extremely long or obstructed labor because of pelvic proportions that are too small for the baby’s head to pass through.
- A difficult delivery that includes the use of forceps.
- Had a forceful manual removal of placenta.
- A fetus position turned from the outside of her body (external cephalic version).
- Inherited uterine abnormalities.
Depending on the type of uterine scar from a cesarean section (low transverse versus a “traditional”, vertical incision), a women may be recommended to not attempt a vaginal birth after cesarean (VBAC), because a trial of labor (TOL) may put her at risk for uterine rupture.
Because of the low risk of uterine rupture, even for women attempting a VBAC, and the desire for women to give birth in the safest and least restrictive environment, the American College of Obstetrics and Gynecology (ACOG) does not recommend that a woman’s TOL after cesarean necessarily take place in a medical facility equipped to perform an emergency cesarean section, but that women and their physicians have “a thorough discussion of the local health care system, the available resources, and the potential for incremental risk” so that both parties make informed choices that they feel comfortable with.
As soon as uterine rupture is suspected, the baby is delivered immediately by emergency cesarean section. A transfusion is almost always necessary, as a uterine rupture causes serious hemorrhaging. Depending on the extent of the damage to the uterus, it will either be surgically repaired, or have to be removed (hysterectomy).