Stopped funding by Regional Healthcare System.

The study aims to determine whether the use of automated intermittent devices for labor analgesia could prevent the increase of instrumental deliveries, with same analgesia.

Moreover it will evaluate if automated devices can allow a reduction of health-care burden.

Epidural analgesia is recognized as the most effective technique to control labor pain, although its possible adverse events. Continuous epidural administration of local anesthetics can stabilize the analgesic block and reduce the anesthesiologists' workload but is associated with an increase in operative vaginal delivery.

Epidural intermittent boluses performed by anesthetist are associated to reduction of dosages, but they could provide insufficient analgesia and they involve the constant anesthetist's presence in the operating room.

This is a multicenter randomized controlled trial with two arms, funded by grant of Regione Emilia Romagna, in which we will compare two different epidural analgesia protocols: anesthesiologist's supervised versus intermittent boluses with PCEA.

Inclusion Criteria:

1. Nulliparous women at full-term pregnancy single fetus and vertex presentation, hospitalized for harbingers of labor and cervical dilation less than 5 cm
2. Numeric Rate Scale > 5

Exclusion Criteria:

1. patients aged under 18 years
2. patients with ongoing administration of oxytocin
3. patients with no indications to epidural analgesia
4. patients with inability to place the epidural catheter for technical difficulty
5. patients with parenteral administration of opioids
6. multiparous women
7. patients unable to understand the objectives and procedures of the study