Uterine rupture in pregnancy is a rare occurrence, but when it happens it can be life-threatening for both mom and baby. A study conducted from 1976 to 2005 showed that uterine rupture occurred in one out of 1,514 pregnancies, or 0.07%. Still, if a uterine rupture does occur, a doctor might have only 10–30 minutes to prevent fetal death or irreversible brain injury.
A uterine rupture (also called a ruptured uterus) is a tear in the wall of the uterus, usually (but not always) in the location of a previous C-section incision (for this reason, many healthcare providers encourage pregnant women who have had prior uterine surgery to try to deliver their babies vaginally). The majority of uterine ruptures happen to women who have had prior uterine surgery, and these ruptures also occur mainly during labor, although in rare cases they can happen spontaneously during the pregnancy. They occur because scar tissue forms when the uterus heals after surgery, and scar tissue is weaker than native uterine tissue. Labor places stress on the scar tissue, which can then tear, leading to internal bleeding, placental injury, or umbilical cord compromise.
Prior uterine surgery includes having a history of a Cesarean section, prior uterine fibroid surgery (called myomectomy), uterine repair surgery (for example, removal of a uterine septum, removal of a portion of the uterus for certain types of ectopic pregnancy (cornual pregnancy, to be specific), or repair of a uterus that was badly injured during a procedure (uterine perforation is a known complication of D&C procedures, and sometimes surgery is required to repair a perforation).
Who’s at Risk for Uterine Rupture?
Thankfully, women who have never had a C-section, a previous rupture, or other uterine surgery are rarely at risk for this complication. That’s not saying it isn’t possible for a woman to experience a uterine rupture without these risk factors. For example, if a woman is having a long labor and Pitocin is being used, uterine rupture can occur if she stops dilating and the Pitocin-augmented labor continues for many hours. This is quite rare, however.
In most cases of uterine rupture there is a history of previous uterine surgery, such as a C-section, and 90 percent of the time the rupture happens at the site of the scar, usually occurring during labor, when the scar is more likely to give way under the stress of the contractions.
Uterine Rupture Symptoms
The “classic” symptoms of uterine rupture are severe abdominal pain, bright red vaginal bleeding, and fetal distress. This combination sometimes occurs during attempted VBAC (Vaginal Birth After Cesarean). An immediate evaluation by a physician is then required. Sometimes, the only sign of a rupture is the sudden onset of fetal distress, and in such cases the baby serves as an early warning system (the “canary in the mine” analogy).
But the diagnosis of a ruptured uterus during labor can also be difficult, even for the best healthcare providers. There may not be any early symptoms, for example, if the baby’s head is engaged in the pelvis and if the patient has an epidural (which prevents vaginal bleeding and blocks pain). In some cases, a rupture might initially just cause internal bleeding (which is invisible).
The diagnosis is delayed until the blood loss is bad enough to cause the mother to go into shock (as evidenced by a drop in blood pressure and fast heart rate) and the baby to develop fetal distress due to the drop in the mother’s blood pressure. One moment the patient says, “I don’t feel good.” Then the baby’s heart rate drops. Then all heck breaks loose.
Other Causes of Uterine Rupture
There are only a few things that can cause a uterine rupture. The most common is scarring from a previous C-section or prior uterine surgery. Other uncommon causes include:
- Placenta previa
- Placenta accreta
- Placental abruption
- Maternal trauma
- Multiple fetuses or Macrosomia (large baby): during labor the uterine wall is thinner due to the uterus being so enlarged, so the risk of rupture is elevated
- Difficulty removing placenta after delivery
It is possible for an unscarred uterus to rupture, but thankfully this only happens in one in 15,000 pregnancies, and almost always during labor.
Uterine Rupture Treatment
If the baby has not already delivered, then an emergency C-section must be performed immediately. The baby’s life is in danger due to loss of blood flow through the uterus to the placenta, and the mother’s life may also be in danger from internal bleeding. The baby might be delivered within minutes and still not make it, or it may end up needing resuscitation and admission to the Neonatal ICU. If the diagnosis is made quickly and the patient is in a hospital equipped for 24/7 emergency C-section, there is a good chance that mom and baby will both pull through okay.
It is unfortunate that some women decide to try to have a VBAC at a birth center or at a small community hospital. The risk of uterine rupture during attempted VBAC is just under 1 percent, but if it does happen at a birth center or at an underequipped hospital, it would be nearly impossible to transfer the patient by ambulance to a properly equipped hospital in time to prevent serious harm to either the baby or the mother.
Fortunately, when the rupture occurs in a C-section scar, the damage to the uterus usually isn’t too severe and the bleeding can be controlled by repairing the uterus. But sometimes the damage to the uterus is extensive, and a hysterectomy is necessary. If there isn’t much damage to the uterus, and if bleeding can be kept under control, then doctors will do their best to repair the uterus. If the blood loss is bad enough, a blood transfusion (or many) will be necessary for the mother. A lot of IV fluid is given to support circulation, and antibiotics are given to prevent infection. If the surgery is long and complicated, the patient might have to go to Intensive Care (ICU) afterward.
Recovery can be difficult. The blood count may be low, leading to weakness and lightheadedness. The patient will likely need a lot of help taking care of the baby. Her breast milk may not come in, or it may be insufficient. There can also be a psychological component to this type of delivery, a kind of post-traumatic stress syndrome, even if the mom and baby did well medically.
Uterine rupture can be one of the most tragic complications of pregnancy and birthing. A normal labor can suddenly become a matter of life or death. If you have any of the above risk factors, it is advisable to deliver your baby in a hospital that is equipped for 24/7 emergency C-section. Thankfully uterine rupture is rare, but the possibility of this complication should always be kept in mind when a patient with any prior uterine surgery is choosing to attempt labor and vaginal birth for her delivery.