5 Questions: Cohen on epidurals and labor
Sheila Cohen
It's a vexing question for many pregnant women: should they get an epidural—a continuous infusion of anesthetic into the spinal column that decreases sensation in the abdomen and pelvis—early in labor or endure the pain until labor is progressing well? A study in last month's New England Journal of Medicine may have more women opting for early relief. Medical Center Report writer Krista Conger turned to Sheila Cohen, MD, professor of anesthesia and of obstetrics and gynecology, to gain a better understanding of the issue.
1. Many women, and their doctors, feel that they should hold out as long as possible before getting an epidural. Why is this?
Cohen: More than 60 percent of the nearly 4 million women who give birth each year in the United States currently receive epidural analgesia. However, some obstetricians still withhold epidurals until late in labor because of fears, based on retrospective studies, that they might slow labor progress and result in more cesarean sections. The current study is part of a growing body of evidence that dispels this belief.
2. The study looks at giving a one-time shot of anesthetic into the fluid surrounding the spinal cord early in labor and then doing the epidural a little later. How common is that practice?
Cohen: This new technique, sometimes called the "walking epidural" is a variation of the traditional epidural. In it, a minimal amount of narcotic is injected, sometimes with a very small dose of local anesthetic, into the spinal fluid where it works directly on the spinal cord to provide rapid, profound analgesia. An epidural catheter is then used to provide continuing pain relief for the remainder of labor. Although this combined technique is commonly used by the Stanford obstetrical anesthesiologists at Lucile Packard Children's Hospital and in most specialized obstetric anesthesia units around the country, it is probably used less frequently in community practices. Like any new technique, training and experience is necessary for it to be used safely and successfully.
3. So what's significant about this study?
Cohen: In this study, 750 first-time mothers who requested analgesia in early labor—in most cases when the cervix was only 2 cm dilated—were randomly assigned to initially receive either the combined spinal-epidural block or a relatively larger intravenous or intramuscular dose of narcotic. The second group received an epidural similar to the first group later in labor when the cervix was more than 4 cm dilated. The physicians then monitored the duration and outcome of the labors in both groups.
The results surprised many obstetricians. Not only were there no differences in the rate of cesarean delivery—about 19 percent in both groups—or of assisted vaginal delivery, but labors were also about 90 minutes shorter in the women with early epidurals. Furthermore, the women who initially received systemic narcotic experienced much more pain in early labor and were eight times more likely to vomit than women who received an early epidural. Their babies were also less alert one minute after birth. In essence, epidurals provided superior pain relief without adversely affecting labor progress or increasing the risk of cesarean section.
Our group has long felt that early epidurals do not delay labor progress and might even accelerate it in the very anxious or uncomfortable patient. This study provides objective evidence to support our practice.
4. Is this study the last word on this question?
Cohen: No. We don't know the mechanism for the shorter duration of labor with the early combined spinal-epidural in this current study. It may be related to the decrease in the mother's adrenaline levels that occurs after she becomes comfortable; adrenaline inhibits uterine muscle contractility and contractions often become more effective after the onset of good pain relief. We do not know whether similar findings would occur with use of different drugs or concentrations, or if a traditional epidural were performed instead of the combined spinal-epidural.
5. Natural childbirth proponents sometimes argue that using any anesthetic during childbirth "medicalizes" a normal physical process. What advice might you offer to a woman who was trying to decide whether to request pain relief during labor?
Cohen: Relief of labor pain—almost the only pain that civilized society has ever labeled as "natural"—has always been controversial. Despite the fact that labor results in severe pain for most women, societal pressures make some mothers feel guilty and inadequate when they "break down" and request analgesia. I would advise a woman to become educated about the available options from reliable, up-to-date sources. I would assure her that the vast majority of women request pain relief in labor and that epidurals, which are generally very safe, are the most effective analgesic method currently available. This current study provides further reassurance that labor should not be adversely affected (and may even be facilitated) by an epidural.
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