Effects of Epidural Labor Analgesia With Low Concentrations of Local Anesthetics on Obstetric Outcomes: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

Low concentrations of local anesthetics (LCLAs) are increasingly popular for epidural labor analgesia. The effects of epidural analgesia with low concentrations of anesthetics on the duration of the second stage of labor and the instrumental birth rate, however, remain controversial. A systematic review was conducted to compare the effects of epidural analgesia with LCLAs with those of nonepidural analgesia on obstetric outcomes.