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 = 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.