Epidural Anesthetic Does Not Slow Labor Progress

Maintaining epidural infusion has no effect on the duration of the second stage of labor when compared with a placebo infusion, according to a new study.

Researchers at Beth Israel Deaconess Medical Center (BIDMC; Boston, MA, USA) and Nanjing Medical University (China) conducted a double-blind, randomized, placebo-controlled trial involving 400 nulliparous women with singleton pregnancies who requested epidural analgesia. All women received patient-controlled epidural analgesia for the first stage of labor using 0.08% ropivacaine with 0.4 micrograms/mL sufentanil. At the onset of the second stage of labor, the women were randomized to receive a blinded infusion of the same solution or placebo saline infusion.

The primary outcome was the duration of the second stage of labor. The results revealed that the duration of the second stage of labor was similar between groups, at 52 minutes. Spontaneous vaginal delivery rate was also similar, at 96.5% for epidural infusion compared to 99% for saline. Pain scores were also similar between groups at each measurement during the second stage, as were incidence of episiotomy, the position of the fetus at birth, Apgar scores, umbilical artery pH, or any other measure of fetal wellbeing. The study was published on October 6, 2017, in Obstetrics & Gynecology.

“We found that exchanging the epidural anesthetic with a saline placebo made no difference in the duration of the second stage of labor. Not even the pain scores were statistically different between groups,” said senior author Philip Hess, MD, director of obstetric anesthesia at BIDMC. “Ethically, if epidural medications result in a negative effect on the second stage of labor, one could argue that a mild increase in maternal pain could be balanced by a successful vaginal delivery. We didn't see any negative effects, but epidural analgesia in the second stage of labor remains controversial and merits follow up studies.”

Epidural analgesia, which is achieved by a mixture of anesthetics and narcotics delivered by a catheter placed near the spine, is considered the most effective method of labor pain relief. In widespread use since the 1970s, epidurals have long been thought to slow the second stage of labor--starting when the cervix is completely dilated and ending when the baby is delivered. Because a longer duration of this stage of labor is associated with adverse outcomes, obstetricians routinely reduce or discontinue epidural pain management in an effort to expedite this main stage of labor.

Related Links:
Beth Israel Deaconess Medical Center
Nanjing Medical University