This, however, does not tell the complete or completely true story. Restrospective data taken from hospitals where epidural analgesia for labor was newly introduced have shown no overall increase in cesarean section rate after the provision of epidurals was begun (Published reference: American Journal of Obstetrics and Gynecology, 2000; 183:974-8). In addition, a number of studies in recent years have shown no relationship between the use of epidurals for labor an the incidence of cesarean section. So what is the real story and why the observation that the two issues are often linked?

RECENT META-ANALYSIS< BR>A recent meta-analysis combined data from previously completed studies to once again demonstrate that there are no statistically significant differences in cesarean section rates between women receiving epidural analgesia and those receiving intravenous medications such as opioids. (Published reference: American Journal of Obstetrics and Gynecology, 2002; 186:S69-S77) This meta-analysis includes data from fourteen studies and more than 4,300 patients. Overall rate of cesarean section was 7.7% for the patients receiving intravenous opioids and 8.0% for the patients receiving epidural analgesia. This small difference of 0.3% was shown to not be statistically significant, i.e. there is essentially no difference between the two groups.

WHAT ELSE DID THEY FIND?
There were some other interesting conclusions drawn by the combined statistical analysis of these fourteen studies. For example, some of the studies reviewed noted a higher incidence of intrumented delivery (forceps delivery, etc.) in those patients that received epidurals. However, in the studies that specifically looked at intrument delivery for "true obstetric indications" versus those performed for "other" reasons did not show a difference. One explanation for this might be that patients that are comfortable (i.e. numb from their epidural) aer more likely to tolerate intrument delivery and therefore the obstetrician might be more willing to consider that as an option. Another might be that the absence of feeling at the time of delivery makes it more difficult for women to coordinate their pushing efforts with contractions. This last effect has been shown to be something that can be overcome with strict and persistent coaching from the labor nurse, delivering physician, etc. However, its significance should not be overlooked because of the possible effect it has on the incidence of forceps delivery.

Additional findings included the fact that there was no difference in the length of first-stage labor between the two groups and also no difference in the incidence of long-term back pain (an issue discussed previously on this site). The issue of back pain, especially, is one that is often of concern to patients when considering the use of epidurals for labor analgesia.

One additional difference that is a significant issue is that maternal fever was more frequent in patients given epidural analgesia. Again, this is a topic that has been discussed on this site before. The mechanism of this effect is unknown but can result in additional and perhaps unnecessary testing in the babies of mothers who develop fevers. It is important to be cognizant of this "side-effect" and to make careful decisions regarding care in light of this issue.

One last significant difference to mention: satisfaction scores were higher in patients receiving epidural analgesia compared to patients receiving intravenous opioids. It should be noted that no comparison was made in satisfaction scores to those patients that required or desired no pain relief. Therefore these satisfaction scores only reflect the experience of patients who desired pain relief and show only the difference in pain relief quality between epidurals and intravenous medications. It has long been known that epidurals give the highest degree of pain relief, so these findings are not surprising.

SUMMARY
The use of epidural analgesia remains a personal choice of the mother who is experiencing labor. However, this information can at least provide the person trying to make an informed decision with additional data about the risks and benefits of epidural analgesia versus intravenous medications. As expected, epidurals continue to prove themselves to be a superior form of pain relief when judged purely by quality of analgesia. However, there are a number of other issues of importance to patients (the increased incidence of forceps delivery, the increased utilization of oxytocin, the increased incidence of maternal fever, etc) that might affect their decision making process.

When it comes to the single issue of cesarean section, however, it appears that epidurals have a fairly neutral effect on whether a cesarean section will be needed or not. This is information that the anesthesioologist should be familiar with and information that should be communicated to the patient in the informed consent process. Therefore, this is an important finding.

So what accounts for the well-known association between epidurals and cesarean section? The prevailing opinion is that patients who are more likely to have cesarean sections are also likely to have more difficult, longer and more painful deliveries. This might be a result of a larger baby, a baby that is not positioned optimally for vaginal delivery, etc. These patients are likely to be the ones that are requesting epidural analgesia since their labor and delivery process is harder to bear. So the data shows an association between epidurals and cesarean section, which there is. However, carefully conducted randomized studies make it clear that an association between two things does not necessarily indicate cause and effect.