Risk factors that make a repeat cesarean necessary
A trial of labor after a previous cesarean section is not recommended for women who have an increased risk of a previous cesarean scar tearing open (uterine rupture). Regardless of risk factors, no trial of labor is safe without the medical facilities and staff needed for an emergency cesarean.
Some health problems make a trial of labor more risky for you or for your baby. You may know about some of these problems early in your pregnancy or long enough before your due date that you can plan accordingly. Situations that make a vaginal birth after cesarean (VBAC) trial of labor more risky include:
- A vertical (classical) uterine incision that reaches above the lower uterus.
- Two or more cesarean scars and no previous vaginal delivery.1
- A cesarean delivery within the past 2 years.2
- A single-layer closure, rather than a double-layer closure, of your previous cesarean section.3
- Previous uterine surgery, such as removal of a uterine growth (fibroid) that has cut deeply into the uterus.
- A narrow (contracted) pelvis, as determined during your last delivery.
- Triplets or more during this pregnancy.
- A medical reason for cesarean in this pregnancy, such as active genital herpes or placenta previa.
Even if you plan a trial of labor, problems that require a repeat cesarean may develop as your due date nears or during labor. You may need a repeat cesarean if:
- Your labor does not begin spontaneously. One medicine used to start (induce) labor, misoprostol (Cytotec), has been linked to a higher risk of uterine rupture during VBAC. (If oxytocin is used sparingly to help a slow labor, it is less likely to increase uterine rupture risk.)1, 4 Some doctors will place a thin tube with a small balloon into the cervix. This can soften the cervix without raising the chance of uterine rupture.
- Placenta previa or placenta abruptio develops. These problems often require a cesarean delivery. However, if you had your first cesarean because of one of these problems, there is no reason to expect that it will happen again.
- The baby is in a breech position. For more information, see the topic Breech Position and Breech Birth.
- You have an active case of genital herpes, which may be transmitted to your infant during a vaginal delivery.
- Fetal monitoring during labor indicates that the baby may be in distress.
- American College of Obstetricians and Gynecologists (2004, reaffirmed 2007). Vaginal birth after previous cesarean delivery. ACOG Practice Bulletin No. 54. Obstetrics and Gynecology, 104(1): 203–212.
- Bujold E, et al. (2002). Interdelivery interval and uterine rupture. American Journal of Obstetrics and Gynecology, 187(5): 1199–1202.
- Bujold E, et al. (2002). The impact of single-layer or double-layer closure on uterine rupture. American Journal of Obstetrics and Gynecology, 186(6): 1326–1330.
- Lydon-Rochelle M, et al. (2001). Risk of uterine rupture during labor among women with a prior cesarean delivery. New England Journal of Medicine, 345(1): 3–8.
Last Updated: April 17, 2009