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.