What is uterine rupture?
Uterine rupture refers to any separation in the wall of the uterus. Although this may happen during any labor, it is most commonly seen in women who have had a previous cesarean birth, or women who have had many pregnancies. We will talk about rupture of a uterine scar. There are two types of uterine rupture:

The first is the more common thinning of the scar. It creates a window-like effect, and the technical term for this is called "dehiscence". It is thought that this occurs in about 1 of every 200 VBAC labors, however it is impossible to calculate the true numbers because the majority of these ruptures are asymptomatic, meaning there is no fetal distress, and the woman is unaware that this has occurred. The only way to detect a dehiscence is to do a manual exploration of the uterus after the birth or if the woman must have a cesarean after she has been laboring. The wound dehiscence heals itself in about 6 weeks and does not increase risk for future pregnancies.

The second type is called catastrophic uterine rupture. This is extremely rare, and according to some sources is no more common during a VBAC labor than in the general population. Catastrophic rupture is when the scar seperates completely, and the fetus is expelled into the abdominal cavity. Prior to the rupture, there are distinctive changes in the fetal heart tones (the baby's heartbeat) called decelerations, where the heartbeat begins to drop significantly before returning to baseline. This is followed by a prolonged drop in the baby's heartbeat. It is imperative that emergency surgery be done at this point. This type of rupture is life threatening to both mother and baby. This is why it is recommended that VBAC births occur in hospitals capable of doing an emergency cesarean.

Okay, now that we are all feeling nervous…the concept of a uterine rupture is very scary. But there is a lot of information out there and knowledge is power, so lets learn more, and put this in perspective. It is important to note that both types classify as uterine rupture as far as many studies and statistics are concerned.

Facts:

1. One in ten American women have had a cesarean birth.
2. The cesarean rate is increasing each year.
3. Cesarean births put women at risk for uterine rupture in future pregnancies.
4. The VBAC rate is declining thanks to fear of litigation and women not receiving options and support.
5. There is hope.

Another theory is called fibroblast proliferation, which means that normal relation of smooth muscle to connective tissue is re-established.

So what?
Well, the importance of this is that the tissue is entirely muscular. Even with thinning, it is all muscle. So there is no area of non -stretchy hardened scar tissue. It is reassuring to imagine your uterus as strong and stretchy.

Uterine rupture- what is the risk?
There have been many studies done to research the risk of uterine rupture. The latest study out of the New England Journal of Medicine studied 17,898 women attempting VBAC.

1. They found the risk of uterine rupture in spontaneous labor (not induced or augmented) to be 0.4%
2. The risk of rupture for augmented labor, that is helped along with pitocin, was 0.9%
3. The risk of rupture in induced labors was 1.0%
4. Prostaglandin induction had a higher rate of 1.4%

There is hope.

Williams Obstetrical Textbook notes that at Parkland Hospital during the years of 1990-1994 there were 74,000 births. There were only 4 uterine ruptures. This is an incidence of 1 in 18,500 deliveries. None of these were VBACs.

Parkland Hospital instituted a policy of not using pitocin to induce labor or augment labor in VBAC deliveries in 1990. At the time of the books last copyright in 2001 there were no uterine ruptures during VBAC labors in those 11 years.

Lets talk incisions!
There are 4 types of incisions made during a cesarean birth.

1. A classical up and down incision
2. An inverted "T"
3. A low vertical incision
4. A low transverse incision (the most common done today, a low bikini line incision)

The risk of rupture with a low vertical incision is 1.1%

The risk of rupture with a low transverse incision is 0.19-0.8%

There are two means by which to suture a uterine incision. Single layer and double layer. A single layer closure is one continuous line of stitches. A double layer closure is two layers of interrupted stitches. The double layer closure is stronger and associated with a much lower risk of uterine rupture.

So what makes me a good candidate for a VBAC?
According to the American College of Obstetricians and Gynecologists, the selection criteria is as follows:

1. One or two prior low-transverse cesarean deliveries
2. Clinically adequate pelvis (to be determined by your practitioner)
3. No other uterine scars or history of rupture
4. Availability of personnel for emergency cesarean

I will add a few other criteria found in my research:

5. Double layer closure
6. Interdelivery interval of greater than or equal to 24 months
7. Maternal age less than or equal to 30 (this doesn't mean that you shouldn't consider VBAC if you are 30 or older)
8. Avoidance of induction agents if possible during labor
9. A previous vaginal birth (before or after the cesarean, having delivered vaginally is protective for some reason. It decreases the risk to 1/5th the rate of rupture noted in women who have not had a vaginal birth.

Important to note!!!
According to Varneys Midwifery Textbook (the queen mother of all midwifery texts):

"Rupture of a low transverse uterine incision, if it occurs is not generally catastrophic or life threatening to either the mother or baby. It is usually a dehiscence (separation) found by later exploration or elected repeat cesarean. To be life threatening, rupture of a uterine scar either extends into the rich blood supply found in the uterine corpus or fundus (the top) or disrupts the placenta, which is normally located in the uterine fundus" (the top).

Let's put this all in perspective stats from Williams Obstetrics and Varney's

The concept of uterine rupture is scary. It certainly is a risk to be considered when thinking about a VBAC. However it is important to note that nothing is with out risk.

Lets say the risk of uterine rupture is 0.19-0.8% with a low transverse incision.

• The risk of miscarriage after amniocentesis is 0.5 to 1% (a procedure offered routinely to many women)
• The risk of a cesarean delivery following induction is 5.9 to 11.9%
• The risk of hysterectomy after an elective cesarean is 0.2%
• The risk of long term affects from an epidural are:
• Backache 19%
• Frequent headaches 4.6%
• Migraines 1.9%
• The risk of fever with an epidural is 15%
• The risk of developing gestational diabetes is 7%
• The risk of a hypertensive disorder (high blood pressure and related issues) in pregnancy is 5-10%
• The risk for preterm birth is 12%

The point of this is not to be doom and gloom. The point is that uterine rupture needs to be put into perspective, that the risk is not an outlandishly high number, when in fact, the risk is very low when proper screening and proper precautions are taken.