Epidural Analgesia During Labour

Randomized single blind trial based on comparing the way the local anesthetic is dosificated during labour. The pain control is evaluated and compared with both dosage techniques (PCEA vs PIEB)using levobupivacaine and fentanyl. The primary objective is to see no differences in pain control(VAS, Visual Analog Scale). The secondary goals are the differences in motor block(Bromage Scale), satisfaction (Likert Scale), the outcome (eutocic, instrumental o cesarean section), second stage of labour time, newborn´s Apgar and pH and total dosis and secondary effects of local anesthetic.