Context.— Epidural labor analgesia, if selected by the
patient, is associated with high cesarean delivery rates. Results of
randomized trials comparing rates of cesarean delivery using epidural
anesthesia vs parenteral opioids are inconsistent.
Objective.— To review the effects of epidural vs parenteral
opioid analgesia on cesarean delivery rates.
Data Sources.— Studies were identified by searching MEDLINE
from January 1966 through January 1998, the Cochrane Database of
Perinatal Trials, and relevant nonindexed journals and abstracts.
Study Selection.— We included all studies that randomized
patients to epidural vs parenteral opioid labor analgesia.
Data Extraction.— Two authors independently extracted data
from 10 trials enrolling 2369 patients. Odds ratios (ORs) for
categorical data, weighted mean differences (WMDs) for continuous data,
and 95% confidence intervals (CIs) were calculated using a
Data Synthesis.— The risk of cesarean delivery did not
differ between patients receiving epidural (8.2%) vs parenteral opioid
(5.6%) analgesia (OR, 1.5; 95% CI, 0.81-2.76). Epidural patients had
longer first (WMD, 42 minutes; 95% CI, 17-68 minutes) and second (WMD,
14 minutes; 95% CI, 5-23 minutes) labor stages. While epidural
patients were more likely to have instrumented delivery (OR, 2.19; 95%
CI, 1.32-7.78), they were no more likely to have instrumented delivery
for dystocia (OR, 0.68; 95% CI, 0.31-1.49). After epidural analgesia,
neonates were less likely to have low 5-minute Apgar scores (OR, 0.38;
95% CI, 0.18-0.81) or to need naloxone (OR, 0.24; 95% CI, 0.07-0.77).
Women receiving epidural analgesia had lower pain scores during the
first (WMD, −40 mm on a 100-mm scale; 95% CI, −42 to −38 mm) and
second (WMD, −29 mm; 95% CI, −38 to −21 mm) stages of labor. The
odds of dissatisfaction were lower with epidural analgesia (OR, 0.25;
95% CI, 0.20-0.32).
Conclusions.— Epidural labor analgesia is not associated
with increased rates of instrumented vaginal delivery for dystocia or
cesarean delivery. Patients receiving epidural analgesia have longer
labors. Patient satisfaction and neonatal outcome are better after
epidural than parenteral opioid analgesia.