[The effects of peridural anesthesia on duration of labor and mode of delivery]. / Influence de l'anesthésie péridurale sur la durée et les modalités de l'accouchement.

OBJECTIVE: To determine the effect of epidural analgesia (EA) on the duration of labour and the mode of delivery. DATA SOURCES: A Medline computerised literature research was conducted from 1989 to 2000 including all the prospective studies comparing EA and systemic analgesia during labour. DATA SYNTHESIS: EA prolongs the first and second stages of labour and increases the rate of instrumental delivery, without neonatal side effects. EA is not responsible for dystocia and caesarean section rate is not increased by this mode of analgesia. The effect of combined spinal-epidural analgesia is comparable to the one of EA on the length of labour and the mode of delivery. Ropivacaine does not appear to be different from bupivacaine in that setting. The benefit of ambulation remains controversial since it does not reduce the incidence of instrumental delivery, compared to conventional EA with similarly diluted local anaesthetic solutions. CONCLUSIONS: Pain relief provided by EA combined to modification of obstetric management (amniotomy, oxytocin) does not impair the rate of caesarean section and dystocia.