Heard someone you know had a uterine rupture? Sounds like a nightmare? Want to know everything about it? Before you read further you must know that yes it is scary but it is a very rare condition and that though you may have one or more risk factors that are mentioned below the chance that you might face this are low. Studies show that a majority of women who deliver after a prior caesarean, have a safe and normal birth. According to the National Health Institute, 992-993 women out of 1,000 give birth without the complication of a uterine rupture.
Uterine rupture or a tear in uterine wall during pregnancy is a very rare complication observed in the last trimester of pregnancy which can cause maternal and foetal distress.
The uterus is a stretchable bag-like structure located in the abdominal cavity and it’s wall is 3 layers thick.
Uterine rupture occurs when the uterine wall is disrupted in such a manner that the contents of the uterus (like the foetus, the placenta, and the umbilical cord) can be expelled into the abdominal cavity.
On the other hand, uterine scar dehiscence or uterine window or scar separation involves the disruption and separation of a pre-existing uterine scar and it does not disrupt the serosa. Hence the contents of the uterine cavity remain within the uterus.
Uterine scar dehiscence is far more common than uterine rupture and only rarely results in major maternal or foetal complications. Although a uterine scar is a well-known risk factor for uterine rupture (most of which arise from prior cesarean delivery), the majority of the events involving the disruption of uterine scars results in uterine scar dehiscence rather than uterine rupture. These two conditions need to be clearly distinguished, as the clinical management and the resulting clinical outcomes differ significantly.
Uterine rupture usually occurs during peripartum, that is the time period shortly before, during, and immediately after delivery. This is obviously because it is the time when the foetus has attained maximum size and the uterus is maximally stretched. It can either occur in women with a native, unscarred uterus or a uterus with a surgical scar from previous surgery done for any reason – previous Cesarean section or any other surgery like a myomectomy (partial removal of diseased uterine wall be it by open surgery or a laparoscopy).
Even in high-risk groups, the overall incidence of a ruptured uterus during delivery is quite low. It occurs at the rate of 1 in 1,146 pregnancies (0.07%). The chances of uterine rupture are even fewer in an unscarred uterus. But if you have undergone a previous Cesarean section or any surgery on the uterus, the risk of a uterine rupture during delivery doubles consequently. Also, higher the number of various risk factors present, more is the chance of rupture, the incidence still being very low.
The possible causes of uterus rupturing are different for an unscarred uterus and a scarred uterus, the later being accountable for most of the cases.
Unscarred uterus is least susceptible to a uterine rupture. The incidence is only 0.012% that is 1 in 8434 pregnancies – almost all the cases being those of second or third pregnancies rather than first pregnancies. So if this is your first delivery and if you have never had any surgery done on your uterus, you need not worry.
Following are the risk factors in an unscarred uterus:
A single cesarean scar increases the overall rupture rate to 0.5%, with the rate for women with 2 or more cesarean scars increasing to 2%. Medical literature suggests that there is an increase in the complications following vaginal birth after previous cesarean section (VBAC) due to uterine rupture. This and the medico-legal fears is the reason why there is a decline in the doctors offering and women accepting planned VBAC in the UK and North America and now also in urban India. Can uterine fibroids rupture? Well, the scar of myomectomy on the uterus (the surgery done to remove the fibroids) can give way to uterine rupture. The fibroids per se causing rupture in unscarred uterus is extremely rare.
Risk factors in a scarred uterus:
There is 3.3. fold increased risk of spontaneous uterine rupture after previous C-section compared with women who undergo elective repeat cesarean delivery. But it is quite interesting to note that if there has been one successful VBAC (vaginal birth after C-section) earlier, the chance of uterine rupture during VBAC subsequently is decreased.
Multiple potential theories exist, but the 2 most obvious are that a successful prior VBAC attempt ensures that –
The upper vertical scar in olden times is now almost obsolete as it carried maximum risk of rupture. The lower transverse scar most commonly used today is least susceptible to rupture.
There is a 3 fold increased risk of a rupture if the interdelivery time between the previous C-section and the subsequent delivery is less.
There is a 3 fold increase in the rate of rupture if the maternal age is > 30 years compared to younger mothers
There is no increased in twin pregnancy compared to singleton pregnancy.
There is a slightly higher risk of rupture if the weight of the baby is more (> 4000 gms)
There is significantly higher risk of rupture if the gestational age is > 40 weeks as usually they are associated with induction of labor.
What happens if scar starts to tear during labor? The initial signs and symptoms are quite nonspecific and that makes the diagnosis difficult, delaying the definitive treatment. The signs and symptoms may vary from being minimal like in a small dehiscence to a severe life threatening one, like in case of a large rupture which involves a major blood vessel. It largely depends on the timing, site, and extent of the uterine defect. Uterine dehiscence at the site of a previous uterine scar is typically serious because the scar has relatively fewer blood vessels.
A mother when in labor or due to lack of experience may not be able to notice any symptom and hence delay the diagnosis and treatment. Following are some symptoms that may indicate a uterine rupture:
These signs are not specific for uterine rupture but only indicative and needs a proper diagonisis by experts.
The consequences of uterine rupture depend on its severity, the time between diagnosis and treatment and the level of medical care available.
Foetal consequences are admission to neonatal intensive care unit, fetal hypoxia or anoxia (decreased or no oxygen to the baby respectively), and neonatal death. The chance of death varies from 6-17% but the incidence of perinatal death associated with uterine rupture is decreasing in the modern era.
Maternal consequences are bleeding, low blood pressure, bladder injury, need for hysterectomy, and maternal death.
Uterine rupture being an emergency needs rapid diagnosis and treatment. Because of the short time available before the onset of irreversible damage, time-consuming diagnostic methods and sophisticated imaging modalities have only limited use. It is only the clinical expertise of the doctor that will help based on the standard signs and symptoms.
One may wonder – is it possible to predict an uterine rupture well in advance and be prepared? It is, but only in selected few cases. Various diagnostic techniques have been used to attempt to assess the individual risk of uterine rupture in selected patients. MRI may aid in evaluating the status of a uterine scar. Ultrasonography may be useful for detecting uterine-scar defects after caesarean delivery by measuring the thickness of the uterus wall. The risk of uterine rupture after previous caesarean delivery is directly related to the thickness of the lower uterine segment, as measured during transabdominal ultrasonography at 36-38 weeks of gestation. The risk of uterine rupture increases significantly when the uterine wall is thinner than 3.5 mm.
The most critical part of the management of uterine rupture is a timely diagnosis and commencement of the treatment as fast as possible. As a rule, the immediate stabilisation of the mother (including fluid resuscitation and blood transfusion) and the delivery of the foetus within 10-37 minutes of uterine rupture is necessary to prevent serious complications to both the mother and the child. The newborn may require an NICU (Neonatal Intensive Care Unit) admission and observation. Later the mother might need a surgical intervention which again may vary from a simple tear repair to removal of the uterus (hysterectomy) depending on the type and the extent of uterine rupture, the degree of bleeding, general condition of the mother and the mother’s desire for future child bearing.
Yes. Uterine rupture can cause significant harm to mother and the baby. It can also result in death. But in a well-managed case with prompt diagnosis and treatment in a well-equipped hospital, the mother and the baby usually do well and death is an extremely rare occurrence. In some cases uterine rupture recovery time is prolonged and needs longer hospital admission adding to the cost. A uterine dehiscence is less harmful and in fact may not cause any trouble at all.
The most direct prevention strategy for pregnancy-related uterine rupture is to minimise the risk factors. The risk modification begins even before the first conception until the last delivery.
What can a mother do?
What can a doctor do?
Although uterine rupture can have dire consequences, it is important to remember that it is extremely rare, and can be harmless if detected early. Being aware and staying alert are the best ways of avoiding a uterine rupture.