Ask an OB: How Often Does Pitocin + Epidural = Cesarean?

Ask an OB is a weekly series with Dr. Maude "Molly" Guerin, MC, FACOG.  If you have questions for her, please share them with us here.

I'd like to know how often Pitocin and epidural, when given together results in a cesarean...ballpark estimate. ~ Safer Midwifery Blog Reader

This question is really two questions: does induction of labor increase cesarean section AND does epidural use increase cesarean section?

Epidural use does NOT increase cesarean section. This is an established and well-tested fact. In the early days of epidural use when the medications used were very strong labor was often prolonged, and OBGYNs misinterpreted this to mean that labor was obstructed and a c section was necessary. As the medications have changed, and the doses have gotten lower over the past 10 years, the effect on labor course has disappeared. We sometimes have to wait longer for women to feel like pushing, but we have learned to be patient. Here is one example of many, many studies that have shown this:

OBJECTIVE: More than 50% of pregnant women in the United States are using epidural analgesia for labor pain. However, whether epidural analgesia prolongs labor and increases the risk of cesarean delivery remains controversial.

STUDY DESIGN: We examined this question in a community-based, tertiary military medical center where the rate of continuous epidural analgesia in labor increased from 1% to 84% in a 1-year period while other conditions remained unchanged-a natural experiment. We systematically selected 507 and 581 singleton, nulliparous, term pregnancies with spontaneous onset of labor and vertex presentation from the respective times before and after the times that epidural analgesia was available on request during labor. We compared duration of labor, rate of cesarean delivery, instrumental delivery, and oxytocin use between these two groups.

RESULTS: Despite a rapid and dramatic increase in epidural analgesia during labor (from 1% to 84% in 1 year), rates of cesarean delivery overall and for dystocia remained the same (for overall cesarean delivery: adjusted relative risk, 0.8; 95% confidence interval, 0.6-1.2; for dystocia: adjusted relative risk, 1.0; 95% confidence interval, 0.7-1.6). Overall instrumental delivery did not increase (adjusted relative risk, 1.0; 95% confidence interval, 0.8-1.4), nor did the duration of the first stage and the active phase of labor (multivariate analysis; P >.1). However, the second stage of labor was significantly longer by about 25 minutes (P <.001).

CONCLUSION: Epidural analgesia during labor does not increase the risk of cesarean delivery, nor does it necessarily increase oxytocin use or instrumental delivery caused by dystocia. The duration of the active phase of labor appears unchanged, but the second stage of labor is likely prolonged. 

(Am J Obstet Gynecol 2001;185:128-34).

The influence of induction of labor on the cesarean section rate is harder to answer because there are lots of variables involved. Over the years it has become clear that if your cervix is ready (dilated, soft, thin, at the front of the vagina, with the head down well), and if this is not your first delivery, induction of labor probably doesn’t increase your c-section rate. If your cervix isn’t ready and if it is your first delivery, your rate is very likely increased, as much as doubled.

This is why we try hard not to induce first-time moms unless they or their baby are in trouble and pregnancy needs to end. Reasons to induce include high blood pressure, reaching 41 weeks, baby dangerously small, diabetes, among others.

So to decrease your c-section risk – be patient and wait for spontaneous labor, unless there are complications that warrant induction.