Effect of epidural vs parenteral opioid analgesia on the progress of labor- A meta-analysis

Context.-Epidural labor analgesia, if selected by the patient, is associate d 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 196 6 through January 1998, the Cochrane Database of Perinatal Trials, and rele vant nonindexed journals and abstracts. Study Selection.-We included all studies that randomized patients to epidur al vs parenteral opioid labor analgesia. Data Extraction.-Two authors independently extracted data from 10 trials en rolling 2369 patients. Odds ratios (ORs) for categorical data, weighted mea n differences (WMDs) for continuous data, and 95% confidence intervals (CIs ) were calculated using a random-effects model. Data Synthesis.-The risk of cesarean delivery did not differ between patien ts 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) l abor 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 in strumented delivery for dystocia (OR, 0.68; 95% CI, 0.31-1.49). After epidu ral 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 f irst (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 dissatisfacti on were lower with epidural analgesia (OR, 0.25; 95% CI, 0.20-0.32). Conclusions.-Epidural labor analgesia is not associated with increased rate s of instrumented vaginal delivery for dystocia or cesarean delivery. Patie nts receiving epidural analgesia have longer labors. Patient satisfaction a nd neonatal outcome are better after epidural than parenteral opioid analge sia.