In this issue of American Family Physician, Vincent and Chestnut1 provide an excellent review of epidural analgesia for labor from the anesthesia perspective. Epidural analgesia is the most effective method for pain relief during labor, and it is relatively safe. As with all other medical procedures, epidural analgesia does have drawbacks. It is much more invasive and expensive than other alternatives for labor analgesia. Hypotension, transient changes in the fetal heart rate tracing and severe headache caused by inadvertent dural puncture are the most common side effects. Other more serious and rare complications may occur, including permanent neurologic injury and death.
From a perinatologist's perspective, the suggestion of Vincent and Chestnut1 that epidural analgesia may be used in the presence of non-reassuring fetal heart rate patterns is concerning. Regional anesthesia in pregnant women with normal uteroplacental function may result in deterioration of fetal acid-base status (severe hypoxic-induced acidemia) caused by reduced uteroplacental blood flow.2,3 In the presence of non-reassuring fetal heart rate tracings caused by uteroplacental insufficiency, epidural analgesia could further impair uteroplacental function and inflict hypoxic brain damage or exacerbate existing damage in already compromised fetuses. Further study is required before epidural analgesia is considered safe for use in parturients presenting with non-reassuring fetal heart rate tracings.
Another issue that deserves more attention is the well-established association between epidural analgesia and the occurrence of maternal fever during labor.4–7 The clinical dilemma is that fever during labor is one of the cardinal signs of chorioamnionitis. Chorioamnionitis is a clinical diagnosis that may present with fever alone. Unusual but devastating consequences (newborn sepsis, severe morbidity or death) may occur if one assumes that fever during labor is caused by epidural analgesia instead of chorioamnionitis. Thus, it is not surprising that at least two studies suggest that epidural-induced fever during labor results in more antibiotic use and invasive work-ups for sepsis in newborns.5,8
The effect of epidural analgesia on labor and delivery is indeed controversial.9 Vincent and Chestnut1 espouse the viewpoint that epidural analgesia is associated with, but does not cause, labor abnormalities or an increase in operative delivery. It is my perspective that epidural analgesia is one of many variables that has caused labor abnormalities, increased operative delivery rates and has contributed to the current high rates of cesarean delivery. However, I do agree that physicians and institutions experienced with epidural analgesia and committed to limiting rates of intervention may use epidural analgesia without increasing rates of cesarean delivery.
Both St. Luke's Hospital of Kansas City, Mo., and Dallas Parkland Memorial Hospital published prospective trials demonstrating an increase in cesarean delivery in patients randomized to receive epidural analgesia and, afterward, both institutions have used epidural analgesia liberally without increasing cesarean delivery rates.4,6,10 Vincent and Chestnut1 would contend that these studies and others suggesting that epidural analgesia increases cesarean delivery are flawed. In contrast, I would maintain that Dallas Parkland Memorial Hospital and St. Luke's Hospital of Kansas City are committed to minimizing rates of intervention and have become more experienced with epidural analgesia. During the years after our trial, there has been a progressive decline in cesarean delivery in cases of dystocia in nulliparous patients using epidural analgesia.
The vast majority of parturients receive their care from physicians and institutions that do not publish formal studies regarding epidural analgesia and labor outcome. The possibility of reporting bias must be considered. Physicians and institutions conducting formal studies are distinctly different from those that do not. Those conducting formal studies are more apt to focus on labor outcome surveillance and on limiting rates of intervention. It is important to recognize that conclusions drawn from research centers may not necessarily apply to other institutions.
This is especially true of a trial that was conducted by Sharma and colleagues6; their institution used a unique combination of management practices that resulted in a 5 percent rate of cesarean delivery in their spontaneously laboring nulliparous population. They concluded that although epidural analgesia did not affect cesarean delivery rates, it did have significant effects on labor. Epidural analgesia resulted in a prolongation in the first stage of labor, more frequent requirement of oxytocin augmentation and more frequent occurrence of maternal fever in labor. Nonetheless, their practice patterns and outcomes should be emulated.
Each individual hospital and its care providers should monitor their own statistics regarding epidural analgesia and intervention rates. It is well known that observation alone will result in outcome improvement (Hawthorne effect). Implementing this surveillance by both obstetric and anesthesia care providers or, better yet, initiating a formal study will have important benefits to patients, clinicians and hospitals. Comparison of nulliparous epidural analgesia and nonepidural analgesia groups is valuable. Epidural analgesia cannot be implicated in having an adverse effect on rates of cesarean delivery if the rates do not differ between nulliparous women using epidural analgesia and those not using epidural analgesia.
Clinicians or hospitals could also use a benchmark to assess their ability to limit or eliminate the potential adverse effects of epidural analgesia. Based on previously published literature, institutional or practitioner “report cards” may be considered (see table). It is unlikely that epidural analgesia has a clinically significant effect on cesarean delivery rates if an institution or a clinician receives a grade of “A.” However, if a less than desirable grade is achieved, then obstetric and anesthesia care providers may consider epidural analgesia and other factors as potential contributors to the excessive cesarean delivery rates.