Uterine rupture is one of the most feared obstetric complications that, if not dealt with immediately (usually by performing an emergency Cesarean section), can result in serious brain damage to the child or the death of either the mother or child. Because it is such a fear-inducing topic that requires the understanding of liability issues as well as actual risk factors, discussions on it tend to become very polarizing.

What is Uterine Rupture?

Simply put, a uterine rupture is any tear in the wall of the uterus, most often occurring during active labor at the site of scar tissue from a previous Cesarean section (C-section). Uterine rupture and the resulting fetal distress have led to cases of cerebral palsy (CP) as well as other brain damage or developmental issues.

There are three layers to the uterine wall: the endometrium (the inner lining of the uterine cavity), the myometrium (the muscular middle layer) and the parametrium (the loose connective tissue surrounding the uterus). In a complete uterine rupture, the contents of the uterus spills into the peritoneal cavity causing internal hemorrhaging. The rupture allows the baby to be pushed out of the uterus. Once the baby is extruded, there is a separation of the placenta from the uterus that is called an abruption. With no connection between the placenta and the uterus, the baby cannot get oxygen. An incomplete rupture is known as a uterine dehiscense. A “window” may form in the uterus, but not break all the way through the thick, muscular myometrium layer. In this scenario, the baby remains contained within the uterus and attached to its blood/oxygen supply. This is not necessarily a medical emergency and doesn’t automatically cancel an attempt at vaginal birth. It is assumed that many dehiscenses go undetected and heal naturally.

Uterine ruptures are relatively rare events—exceedingly rare for women who’ve never had a C-section, other uterine surgery or previous rupture. 6 out of 100 uterine ruptures result in the serious brain damage or death of the unborn child. These ruptures are medically termed “catastrophic.” Claims vary, but it is often suggested that if a baby isn’t delivered within 16-17 minutes after a uterine rupture, the results will likely be “catastrophic.”

Vaginal Birth after Cesarean (VBAC)

Vaginal birth after cesarean (VBAC) is the practice of delivering a baby vaginally after a previous pregnancy resulted in a C-section. As sited by numerous sources, according to the American Pregnancy Association, 90% of women who have undergone C-sections are candidates for VBAC, of which approximately 80% will successfully give birth vaginally.

With some minor variations, there are two basic types of incisions used for C-section surgeries.

• The vertical (classical, midline-vertical) incision used to be the norm. Now used only in special circumstances, such as an extremely premature baby. Amongst other things, it can result in a higher incidence of future rupturing.
• The horizontal (low transverse, Munro-Kerr) incision is the most common type used today. This method results in less blood loss, fewer infections and a less conspicuous scar. Also, the myometrium muscles are thicker and stronger in this lower portion of the uterus, making a repeat rupture less likely.

What Causes the Uterus to Rupture?

When a rupture does occur, it is most often caused by the stress of contractions. The scar tissue from a previous C-section should grow and stretch naturally with the progression of the pregnancy, but can be stretched thin enough to fail the rigors of an intense labor. Some believe that an ultrasound done in early labor can reveal how thin the scar tissue has become and helps point to the likelihood of a rupture.

If labor-inducing drugs such as Pitocin are introduced, the contractions can become even stronger and more violent. Likewise, using prostaglandins to soften the cervix for dilation also increases the risk of uterine rupture.

Signs that a rupture has occurred may include a slowing of the fetal heart rate (bradycardia), pains in the mother’s abdomen, vaginal bleeding, rapid pulse, signs of shock, the slowing or cessation of labor, pains in the mother’s chest or a radical change in the appearance of the woman’s abdomen due to the fact that the fetus may now be outside the uterus. Unfortunately, these indicators are not present with every uterine rupture.

Cerebral Palsy from Uterine Rupture

In the event of a complete rupture, the fetus is most likely to lose its placental connection to blood and oxygen. Asphyxia is the condition whereby the body and brain do not receive adequate oxygen supply. While asphyxia’s role as a principal cause of cerebral palsy has been debated since the days of Sigmund Freud, it now universally accepted that asphyxia is at least one of several possible causes of cerebral palsy. Any brain damage or brain malformation occurring before, during or after birth can lead to cerebral palsy.

Controversy

There are many who are convinced that uterine ruptures actually present a statistically lower risk than what women without prior C-sections face during child birth from complications such as placental abruption, umbilical cord prolapse or shoulder dystocia. They believe that because current US health law and medical-ethical guidelines require that women who have had a previous C-section be offered vaginal birth as an option, these women are often scared away from that option in an effort to defray costs and liabilities to hospitals and physicians. For this reason, finding consistent statistics or use of empirical data on the internet can be difficult.

It is accepted that a VBAC candidate needs to be more closely monitored than a woman who has never had a C-section because the early signs of a rupture are not always obvious. Currently, only about half of the hospitals in the United States even permit VBACs. Most insurance companies and the hospitals that permit VBACs require that beginning with the onset of labor, a fully staffed operating room as well as a complete neonatal intensive care team be on standby. Because labor can take many hours, this can prohibitively tie up valuable personnel and hospital space.

Conclusion

Even presented in the worst possible light, VBAC deliveries remain popular and relatively safe. It is the responsibility of the primary care giver to give candidates a comprehensive picture of the risks and advantages of both VBAC and elective C-section so the patient can make an informed decision on which course to take. Statistically rare or not, uterine rupture is an extremely traumatic event for both mother and baby, one that can deprive the unborn child of invaluable oxygen and blood, possibly leading to cerebral palsy. Obviously, the key to a successful delivery in the event of uterine rupture lies in the vigilant monitoring of the mother and fetus from the very onset of labor, whether naturally occurring or chemically induced, as well as having all the necessary resources available should such an emergency occur.