A Randomized Double Blind Clinical Trial Comparing Programed Intermittent Epidural Boluses (PIEB) Versus Patient Controlled Epidural Analgesia (PCEA) With Epidural or Combined Spinal-epidural (CSE) Technique

Women in labor receiving epidural analgesia may experience breakthrough pain (BP) that requires the use of additional medication and that is a source of dissatisfaction with the analgesic treatment for labor.

The investigators can define two types of BP: 'primary breakthrough pain' is the first moment when the patient requests analgesia during labor. 'Secondary breakthrough pain' can be defined as the time a previously effective epidural analgesia turns ineffective.

The BP may have multiple causes, such as delivery progression and catheter misplacement. There is no single pattern to provide adequate neuraxial analgesia for labor, but for certain patients and specific clinical situations some methods provide advantages over others.

The choice of a suitable system of epidural drug delivery has an important role in getting proper analgesia and a low incidence of breakthrough pain during labor. In order to develop preventive strategies for BP, some clinical scales to estimate its incidence rate have been described. Among risk factors for BP the investigators can include: Nulliparity, epidural catheter placement at an earlier cervical dilation, neonatal weight and technique performed (epidural versus combined spinal-epidural - CSE).

In addition, technological development has offered us new treatment modalities of pain management during childbirth have evolved recently to improve maternal satisfaction, as well as to treat and prevent BP: Patient Controlled Epidural Analgesia (PCEA) added or not to a continuous epidural infusion (CEI), computer integrated PCEA (CI-PCEA) and automatic or programed intermittent epidural boluses (PIEB).