What is Uterine Rupture?
A uterine rupture is a severe medical condition where the whole wall of the uterus, including its inner, middle, and outer layers, tears apart. Doctors need to be on the lookout for symptoms of this condition as it can lead to serious health risks and even death for both the woman and her baby. Uterine ruptures usually occur in pregnant women, although it can also happen in non-pregnant women if their uterus is damaged by trauma, infection, or cancer.
Uterine dehiscence is a related condition. It involves a partial tearing of the uterus and can result in a ‘uterine window’, a term used to describe the thinning of the uterine wall to the point where the baby can be seen through it. Often, uterine dehiscence is discovered by accident in patients without any symptoms. As there’s no one-size-fits-all way to manage this condition. For uterine dehiscence in patients who are at full-term pregnancy, cesarean delivery (surgical delivery through the abdomen) is usually the way to go. But if it happens before the full term, a wait-and-see approach has also been found to be effective.
The difference between uterine dehiscence and uterine rupture can sometimes be confusing as they are frequently used interchangeably, but we should distinguish them.
Recently, there has been growing interest in uterine rupture because more patients wish to have a vaginal birth after a cesarean delivery, which is known as a trial of labor after cesarean delivery (TOLAC). The possibility of a uterine rupture is a key consideration when explaining this option to patients. If a vaginal delivery is successful after a cesarean delivery, this is termed a VBAC, or vaginal birth after cesarean.
What Causes Uterine Rupture?
In pregnant women, there are two groups that are at a higher risk for uterine rupture, which is a tear in the uterus: women who have had previous surgery resulting in a scar on the thick layer of muscle that makes up most of the uterus (myometrium), and women with no such scars. The reasons and risk factors for these two types of people are not the same.
Ever since the 1970s, the use of cesarean section (C-section) for childbirth has been on the rise in the United States. To help lessen the number of C-section births, some doctors have started recommending “trial of labor after cesarean” (TOLAC), which is when a woman tries to give birth naturally even after having a C-section in the past. TOLAC has been found to lower the chances of a mother dying during childbirth.
However, that only happens if TOLAC results in a successful natural birth. If a woman tries TOLAC but still ends up needing a C-section, her health risks are higher than if she’d just scheduled a C-section from the start. For women who try TOLAC, the risk of uterine rupture is a major concern. In fact, it’s 15 to 30 times more likely to happen in women who try TOLAC compared to those who schedule repeat C-sections.
If a woman trying TOLAC has had a specific type of C-section cut (midline or classical incision), her chances of uterine rupture are two to three times higher than if her previous C-section cut was a low segment transverse incision. The drug misoprostol, when used in TOLAC, has been linked with higher rates of uterine rupture, so doctors now usually advise against its use in this situation.
Uterine rupture can also happen in women who haven’t had any type of surgery on their uterus, but it’s not as common. When it does happen, though, it’s usually more dangerous for the mother and baby than when it happens in a woman with a scarred uterus. The causes for this type of rupture usually fall into one of the following categories: physical injury, a genetic disorder that weakens the wall of the uterus, lengthy use of drugs to induce or speed up labor, or a stretching of the uterus beyond its capacity.
In the United States, most serious abdominal injuries during pregnancy are due to falls or car accidents. The possibility of such injuries leading to uterine rupture is why doctors keep a close watch on the unborn baby after any kind of blunt abdominal trauma. Uterine rupture can even occur during procedures that doctors use to manually turn the baby inside the womb. That’s why some doctors avoid using certain types of anesthesia that might hide the pain that could indicate a uterine rupture.
Genetic disorders like Ehlers-Danlos and Loeys-Dietz can weaken the uterine wall and increase the risk of rupture. For instance, if a woman has a uterine rupture without ever having had a C-section, doctors might use that as an indication that she might have a certain type of Ehlers-Danlos syndrome.
Drugs used to induce or speed up labor, such as oxytocin, can put a lot of stress on the uterine wall and lead to a rupture, especially if labor is obstructed. Conditions like gestational diabetes with a large baby (macrosomia), excess amniotic fluid (polyhydramnios), multiple pregnancies, and fibroids can also stretch the uterine wall beyond its limit, which can increase the risk of rupture.
Risk Factors and Frequency for Uterine Rupture
Uterine rupture, which is an emergency situation during childbirth, is gradually becoming more common worldwide. Generally, it happens once in every 5,000 to 7,000 births. The risk of a uterine rupture is particularly higher in women who have had a cesarean delivery before.
- The chances of uterine rupture is about 1% if a woman has had one cesarean delivery in the past, and rises to approximately 3.9% if she has had more than one.
- For women who’ve never had a cesarean delivery before, or have an unscarred uterus, the risk of a rupture is much less, occurring once in every 10,000 to 25,000 deliveries.
- Unfortunately, the incidence of a uterine rupture in an unscarred uterus is higher in developing countries. This is likely due to the limited availability of medical interventions that can help manage difficult childbirths, such as instrument-assisted delivery or cesarean delivery.
Signs and Symptoms of Uterine Rupture
Uterine rupture, which is the breaking of the muscular wall of the uterus, can result in different symptoms depending on whether the woman has an epidural, a previously wounded uterus, and the location of the rupture.
Women suspected of uterine rupture should be quickly assessed for hemodynamic stability. This means checking their blood pressure and heart rate for signs of low blood pressure (hypotension) and a rapid heart rate (tachycardia). Symptoms of hypotension include feeling light-headed, dizzy, nauseous, and anxious, and also vomiting. Vaginal bleeding, which may appear as light spotting or intense bleeding soaking their underwear should also be monitored.
Bladder injury is not uncommon with uterine rupture. That is why urine should be checked for blood if uterine rupture is suspected. Pain along with the presence of pink, red, or brown urine or blood clots in the urine could indicate bladder injury.
Women with uterine rupture may also report sudden abdominal pain that feels like a “ripping” sensation or very painful contractions. Blood irritating the diaphragm, a sheet-like muscle underneath the ribcage, could also lead to chest pain similar to the pain from a heart attack.
The baby’s heart rate could also provide clues. Slow heart rate in a baby, reduced variability, or late decelerations could mean the baby is not getting enough blood. If there are no heart sounds from the baby, ultrasound is required to check the baby’s heartbeat.
- Sudden abdominal pain described as a “ripping” sensation
- Very painful contractions
- Chest pain similar to the pain from a heart attack
- Slow heart rate in the baby, reduced variability, or late decelerations
Physical signs in women with uterine rupture include pain in the middle of their abdomen and tenderness even if they have an epidural treatment for pain. This could hint to changes in the shape and contraction pattern of the uterus.
An internal examination could show evidence of the rupture such as new blood, clots, or tissue from pregnancy in the vaginal canal. The vaginal canal is not normally filled with blood unless the rupture extends to the vagina or cervix. The examination may also reveal other sources of bleeding or changes in the position of the baby.
Testing for Uterine Rupture
If there’s any vaginal bleeding during pregnancy, it’s important to rule out a condition called uterine rupture. This is a serious situation that can harm both the mother and the baby. The typical signs of a uterine rupture are sudden stomach pain, vaginal bleeding, change in your baby’s heartbeat, and change in the pattern of contractions. However, many people don’t experience these symptoms.
To help diagnose a minor uterine rupture, your doctor might use imaging tests like X-rays, and lab tests. But if the rupture is significant, imaging isn’t suitable because the priority will be to deliver the baby and control bleeding as quickly as possible.
An important starting point in lab tests is to check your hemoglobin or hematocrit levels, which can give an idea of blood loss. If there’s a lot of bleeding, additional tests that check how well your blood is clotting might be needed. If there’s not much bleeding yet, testing the initial hemoglobin or hematocrit levels can help monitor for continued blood loss.
If you are stable and the rupture is possibly minor, an ultrasound can be useful to rule out other reasons for vaginal bleeding, like a low-lying placenta (placenta previa), separation of placenta from the womb (placental abruption), or miscarriage (spontaneous abortion). Certain signs seen in ultrasound suggest a uterine rupture. These include issues with the wall of the uterus, a collection of blood (hematoma) next to a scar from a previous cesarean section (hysterotomy scar), fluid in the abdominal cavity (peritoneum), lack of amniotic fluid (anhydramnios), or part of the baby being outside the uterus.
In the end, the definite diagnosis of uterine rupture is often made during a surgical opening of the abdomen (laparotomy), when blood in the abdominal cavity (hemoperitoneum) and parts of the baby are seen outside the uterus.
Treatment Options for Uterine Rupture
If the womb (uterus) tears, immediate action is needed to protect both mom and baby. A delay can increase the danger for both. Often, the baby’s heart rate will slow down if rupture happens. To respond to this, an emergency C-section – even a surgery to examine the stomach and pelvic area – will be done right away.
Typically, general anesthesia (which puts you to sleep) is required for the surgery to happen quickly. Even when epidural anesthesia (anesthesia that numbs the lower half of your body) has been given during labor, it would take 5-15 minutes to provide a surgical level of pain relief, which may be too long in this situation.
Moreover, general anesthesia gives more control over the mom’s acid-base balance and breathing, stabilizes her airways, and relaxes her muscles, which helps with the operation. It helps ensure safety in situations of unstable blood pressure and serious bleeding.
A uterine rupture needs both baby delivery and stopping mom’s bleeding at the same time. Another wide tube (IV line) should be inserted and blood should be ordered and brought to the surgery room. If it’s not possible to quickly insert an IV line, a bigger tube should be placed directly inside a large vein. Initially, resuscitation (first aid to restore breathing/circulation) may be done by providing an electrolyte solution called Lactated Ringer’s. Quick and large volume blood loss should signal the need to transfuse blood early. If bleeding can’t be controlled quickly, an arterial line (a tube inserted into an artery) will allow for better monitoring of blood pressure and frequent blood testing.
When the surgery begins, a straight cut down the middle of your belly, rather than a bikini-line cut (Pfannenstiel incision), would typically be preferred if internal bleeding is expected. This is because a midline cut gives a better view to find where the bleeding is coming from and might shorten the time from surgery to delivery.
In cases where the tear is small, it may be possible to repair the womb. But, if the blood pressure becomes unstable or the uterus is seriously injured, the uterus may need to be removed (hysterectomy). About one in three women who have a womb tear will need a hysterectomy.
What else can Uterine Rupture be?
When a woman experiences vaginal bleeding during the second and third trimesters of her pregnancy, along with sharp abdominal pain, doctors will consider many possible reasons for these symptoms. Potential conditions might include:
- Spontaneous abortion or miscarriage, which is typically identified by seeing fetal tissue within the cervical canal during an examination
- Bloody show, which is a discharge of mucus and blood that can happen up to three days before labor starts
- Placenta previa, where the placenta covers the cervix. It often presents as painless bleeding yet can sometimes cause contractions and can usually be confirmed by an ultrasound
- Placental abruption, meaning the placenta has separated from the uterus before birth. This is often signaled by bleeding, sudden abdominal pain, and ongoing, crampy contractions
- Uterine rupture, which is rare but can lead to serious complications. Previous cesarean deliveries increase the risk of a rupture.
It’s important to diagnose these conditions correctly as each can present risks to both the mother and baby. Physicians use various diagnostic tools, such as ultrasonography, although it can struggle to detect some issues, an example being placental abruption. Therefore, doctors will always base their diagnosis on a comprehensive evaluation of all symptoms and circumstances.
What to expect with Uterine Rupture
With immediate medical attention and resuscitation, the majority of women experiencing a uterine rupture survive. The risk of death in women experiencing a break in an unscarred uterus is higher (10%) compared to women with a previously scarred uterus (0.1%). The mortality rate for newborns following a uterine rupture ranges between 6% and 25%.
The likelihood of another rupture happening after a uterine repair is not well defined. This is because it’s uncommon for uterine ruptures to occur and when it does, in many cases, women may require a procedure known as a hysterectomy – which is the surgical removal of the uterus. Some small studies conducted outside the U.S. showed a recurrence rate of 33% to 100%, but these may not be fully representative. Evidence suggests that the recurrence rate could be higher if the first rupture happens in the top part of the uterus, known as the uterine fundus.
Considering the risks to both the mother and the baby of a potential repeat rupture, most obstetricians – doctors that specialize in childbirth- advise a repeat cesarean delivery between the 36th and 37th weeks, before labor starts.
Possible Complications When Diagnosed with Uterine Rupture
The seriousness of problems for the mother and baby during a womb rupture depends on where and how big the rupture is, and how quickly surgery is performed. Lateral ruptures, ones on the side, can be worse than those in the middle, perhaps because the side of the womb has more blood vessels. The longer it takes to perform surgery, the more the mother may bleed, increasing the risk of a clotting disorder and leaving the baby without enough oxygen for a longer time.
The risk of a rupture in a womb that hasn’t been scarred before can result in more severe outcomes than a rupture in a womb that has been scarred. These outcomes include more bleeding, an increased chance of needing a hysterectomy, and a higher rate of different forms of maternal problems like death, hysterectomy, blood transfusion, or urinary system injury.
The occurrence of composite problems in the baby’s nervous system, such as bleeding within the ventricles of the brain, seizures, death, or lack of blood flow to the brain, is also higher when the rupture involves a non-scarred womb, compared to a scarred womb. The rate of baby death is 10% for non-scarred wombs and 2% for scarred wombs.
Factors Affecting Rupture Outcome:
- Location and size of the rupture
- Speed of surgical intervention
- Type of rupture (lateral vs midline)
- Scarred or unscarred womb
Possible Outcomes After Rupture:
- Increased maternal blood loss
- High risk of coagulopathy (clotting disorder)
- Longer fetal exposure to low oxygen
- Maternal issues (death, hysterectomy, blood transfusion or injury to urinary system)
- Baby’s nervous system problems (intraventricular hemorrhage, seizure, death, or brain ischemia)
- Fetal death rate (10% for non-scarred wombs and 2% for scarred wombs)
Recovery from Uterine Rupture
The plan for care after surgery depends on how blood loss affects blood clotting, maintaining the right acid-to-base ratio in your body, and keeping your circulatory system stable. More often than not, patients who have a rupture in the uterus are usually healthy before the incident. As such, their bodies can usually handle the loss of blood well. However, if patients continue to lose blood, have an increased (more than 2 mmol/L) and rising blood lactate (a substance produced when the body breaks down carbohydrates for energy), and need drugs to maintain blood pressure, they might need to be admitted to the intensive care unit after surgery.
Preventing Uterine Rupture
To protect both the mother and the baby from a serious condition called uterine rupture, it’s vital to take steps to prevent it. Certain women are at higher risk, such as those who have had many pregnancies, are carrying more than one baby, are older, or have disorders affecting their connective tissues. These women need to be particularly careful with the use of oxytocin, a hormone that stimulates contractions during labor.
Similarly, specific procedures that can lead to uterine rupture, such as internal baby turning (inside the womb) and external baby turning, should be done gently and after thoughtful decision regarding the type of anesthesia to be used. Strong pressure should not be applied to the womb during the second stage of labor to avoid uterine rupture. This practice does not speed up labor and increases the risk of uterine rupture.
Women who have these risk factors should learn about the early signs of uterine rupture. It’s also advisable that women at high risk for a rupture should live near their delivery hospital to ensure quick access to medical care.
