ObjectivesTo systematically review the efficacy and safety of sufentanil versus fentanyl used in patient-controlled intravenous analgesia (PCIA) after cesarean section.MethodsAn online search of computerized searches of the database of MEDLINE (OVID), Web of Science, The Cochrane Central Register of Controlled Trials, PubMed, EMbase, CNKI, WanFang Data, VIP and SinoMed were conducted. Randomized controlled trials published since the inceptions of these databases until April 1st 2018, involving the comparison of sufentanil versus fentanyl for PCIA after cesarean section were included. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies. Then, meta-analysis was conducted using the RevMan 5.1 software.ResultsA total of 19 studies were included. The results of meta-analysis showed that, compared with the fentanyl group, the sufentanil group had statistically significant lower VAS scores at 4-hour (MD=–0.99, 95%CI –1.03 to –0.95, P<0.001), 8-hour (MD=–0.30, 95%CI –0.40 to –0.21, P<0.001), 12-hour (MD=–0.54, 95%CI –0.62 to –0.46, P<0.001) and 24-hour (MD=–0.35, 95%CI –0.41 to –0.28, P<0.001); statistically significant higher Ramsay scores at 4-hour (MD=0.72, 95%CI 0.66 to 0.78, P<0.001), 8-hour (MD=0.93, 95%CI 0.86 to 1.00, P<0.001), 12-hour (MD=0.98, 95%CI 0.91 to 1.05, P<0.001), 24-hour (MD=0.07, 95%CI 0.03 to 0.11, P=0.000 5), 48-hour (MD=0.05, 95%CI 0.03 to 0.08, P<0.000 1). As for the adverse reactions, sufentanil group had lower risks of having nausea and vomiting (RR=0.25, 95%CI 0.19 to 0.31, P<0.001), pruritus (RR=0.41, 95%CI 0.30 to 0.57, P<0.001), dizziness (RR=0.27, 95%CI 0.17 to 0.44, P<0.001) and urinary retention (RR=0.35, 95%CI (0.15, 0.82), P=0.02).ConclusionsThe current evidence shows that, sufentanil has better analgesia and sedative effects, and less risks of adverse reactions for safer clinical use.