The effect of adding a background infusion to patient-controlled epidural labor analgesia on labor, maternal, and neonatal outcomes: a systematic review and meta-analysis.

Background: Patient-controlled epidural analgesia (PCEA) has gained popularity, but it is still unclear whether adding a background infusion confers any benefit.
Methods: A systematic literature search in PubMed, Embase, CINAHL, LILACS, CENTRAL, Clinicaltrials.gov, and ISI WOS was performed to identify randomized controlled double-blind trials that compare PCEA-only with PCEA combined with a continuous infusion (PCEA + CI) in parturients. The data were subjected to meta-analyses using the random-effects model. Our primary outcome was the incidence of instrumental vaginal delivery. Secondary outcomes were incidences of spontaneous vaginal and cesarean deliveries, duration of labor, analgesic outcomes, maternal outcomes (visual analog scale scores for pain, maternal satisfaction, nausea, pruritus, hypotension), and neonatal outcomes (Apgar score, umbilical artery pH).
Results: We identified 7 trials with a low risk of bias, reporting on 891 parturients, for inclusion in our systematic review. The risk of instrumental vaginal delivery was increased in the PCEA + CI group, risk ratio (RR) 1.66 (95% confidence interval 1.08-2.56, P = 0.02; I = 0%); the RR for cesarean delivery was 0.83 (95% confidence interval 0.61-1.13, I = 0%). The second stage of labor was prolonged (weighted mean difference 12.3 minutes, 95% confidence interval 5.1-19.5 minutes, P = 0.0008; I = 0%) in the PCEA + CI group. Fewer patients in the PCEA + CI group required physician-administered boluses (RR 0.35 [95% confidence interval 0.25-0.47, P < 0.00001; I = 0%]). No differences regarding maternal adverse events (nausea, pruritus, hypotension) or neonatal outcomes (Apgar scores <7, umbilical artery pH) were observed.
Conclusions: On the basis of current evidence, no conclusion can be drawn regarding the risks or benefits of adding a continuous background infusion to PCEA compared with PCEA-only epidural labor analgesia. Further high-quality studies involving a sufficient number of patients are required.