The Effect of Combined Spinal-Epidural Versus Epidural Analgesia in Laboring Women on Nonreassuring Fetal Heart Rate Tracings: Systematic Review and Meta-analysis

BACKGROUND: Combined spinal epidural labor analgesia has gained popularity, but it is unclear whether this technique is associated with a higher incidence of nonreassuring fetal heart rate (FHR) tracings compared with epidural analgesia. Our meta-analysis aimed at comparing the incidence of nonreassuring FHR tracings between the 2 neuraxial techniques. METHODS: Databases were searched to identify randomized controlled trials that compared the incidence of nonreassuring FHR tracings, as defined in the individual studies, after combined spinal epidural versus epidural analgesia in laboring women. Risk ratios (RRs) and 95% confidence intervals (CIs) were calculated using the random-effects model. We performed a subgroup analysis for studies using low-dose epidural bupivacaine concentrations (<= 0.125%) for epidural analgesia. RESULTS: Seventeen trials including 3947 parturients were retrieved that compared the 2 neuraxial techniques. All trials used intrathecal opioids in 1 study arm. The pooled effect estimate of low- and high-dose epidural bupivacaine studies together showed a significantly increased risk of nonreassuring FHR tracings with the combined technique (RR 1.31, 95% CI 1.02-1.67, P = .03, I-2 = 18%). A subgroup analysis of 10 trials using low-dose epidural bupivacaine found a RR for nonreassuring FHR tracings between combined spinal epidural and epidural analgesia of 1.12, 95% CI 0.93-1.34, P = .18. In a sensitivity analysis of those low-dose epidural bupivacaine studies that ensured blinding of the outcome assessor, the RR was 1.41, 95% CI 0.99-2.02, P = .06. CONCLUSIONS: Combined spinal epidural labor analgesia was associated with a higher risk of nonreassuring FHR tracings than epidural analgesia alone. In the subgroup analysis comparing combined spinal epidural with low-dose epidural labor analgesia, the 95% CI contains a clinically significant difference between groups; moreover, the 95% CI overlaps with the 95% CI of the comparison of the combined low- and high-dose epidural techniques. Therefore, it cannot be concluded that there was no difference between combined spinal epidural and low-dose epidural techniques.