This will be a prospective, randomized, double blind, controlled clinical trial.

Epidural analgesia (EP) is currently the method of choice to ensure the comfort of the parturient during childbirth. Technical and pharmacological advances in recent years have made it possible to provide patients with high quality analgesia with individualized control, associated with extremely limited motor block. However, sometimes this technique fails due to a prolonged delay in action, or insufficient sensory block.

An alternative technique has become popular in recent years, the combined peri-spinal anesthesia also called sequential (CSE). It combines the administration of low doses of local anesthetics and/or intrathecal opiates before the placement of the catheter in the epidural space and the use of the catheter as in a classical technique. This technique would allow a more rapid onset of analgesia, a more complete relief of the patient, and a lower degree of failure. However, it could be accompanied by a greater risk of maternal hemodynamic instability, fetal bradycardia, and a longer expulsion period. In addition, the effectiveness of the catheter injection can only be assessed when the effects of the spinal injected drugs have worn off.

In order to limit these undesirable effects, it has been proposed to perform a dural puncture as performed in the sequential technique but without intrathecal drug injection (DPE). In this way, a "tunnel" is created, allowing the diffusion of drugs from the epidural space to the subarachnoid space. Thus, the initiation of anesthesia would be faster with a lower risk of lateralization compared to the standard epidural, also allowing a decrease in the consumption of local anesthetics and without the undesirable effects of the sequential. Although this technique recently introduced in obstetrical analgesia appears promising, very few studies to date have evaluated its effectiveness and safety.

The hypothesis of the study is that the Epidural with Dural puncture (DPE) provides a higher quality of analgesia than standard epidural while having fewer adverse effects than combined epidural, in particular a lower incidence of maternal hypotension.

The primary objectives are:

• testing the quality of analgesia with DPE compared to PE and CSE. This will be assessed by determining the area under the curve of Visual Analog Scale (VAS) measurements observed from the beginning of obstetric analgesia and throughout the delivery.
• testing the rate of maternal hypotension with DPE compared with PE and CSE, with hypotension defined as a decrease in systolic blood pressure (SBP) greater than 15% from the SBP measured at the time of the parturient arrival in the labor room, a SBP < 90 mmHg, or any decrease in pressure associated with disabling symptomatology (dizziness, yawning, nausea).

For this purpose, the investigators will randomize a total of 90 patients, 30 in each of the groups. The patients will receive one of the three techniques, all of them will benefit from the administration of epidural analgesia with low concentration local anesthetics and opioids on a Intermittent bolus modus (PIB). Patients assigned to the combined spinal epidural modus will receive a injection of a small quantity of local anesthetics and opioids (Levobupivacaine 2.5mg and Sufentanyl 2.5 mcg) in the intrathecal space. A non-blinded anesthesiologists will perform the anesthetics technique and leave the room immediately; a blinded anesthesiologists will do the data collection and act according to protocol if the patient in case of pain non controllable by the patient controlled anesthesia, in case of hypotension or any other possible complications.

Data collection will take place before starting the locoregional anesthesia technique, at the moment when the anesthetists non blinded leaves the room, 10 minutes, 15 minutes, 30 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 6 hours after the start of the analgesia and at the moment of the expulsion of the baby.

Patients and care providers will be blinded to which technic is being given. Data will be statistically analyzed using area under the curve and two-dimension variance analysis.

Inclusion Criteria:

• Pregnant women at term (37-42 weeks of amenorrhea)
• American Society of Anesthesiologists (ASA) class 1 or 2
• no language barrier, i.e; speaking French, Dutch or English or accompanied by a reliable translator
• single pregnancy
• Parity 1 , 2 or 3
• cephalic fetal presentation
• active labor with cervical dilatation less than 5 cm

Exclusion Criteria:

• Contraindications to neuraxial anesthesia
• major pathologies of pregnancy (preeclampsia)
• decompensated gestational diabetes
• diabetes type 1 or 2
• known serious fetal pathology
• maternal previous diseases increasing the risk of caesarean section (caesarean section, uterine malformation, scarred uterus, surgery of the uterine cervix)
• fourth or more deliveries
• extreme pre-pregnancy BMI (< 18 or > 40)

Patients will be randomized by envelopes. A non-blinded anesthesiologists will perform the anesthetics technique and leave the room immediately; a blinded anesthesiologists will do the data collection and act according to protocol if the patient in case of pain non controllable by the patient controlled anesthesia, in case of hypotension or any other possible complications.