The addition of morphine to a local anesthetic when performing an epidural analgesia during labor analgesia has improved the efficiency and the action duration of analgesia. One limitation of this technique is the time of installation of the analgesic effect (about 30 minutes) when using the only epidural. Therefore, the technique of sequential combined spinal epidural was introduced. This is to shorten the installation time by direct injection into the cerebrospinal fluid. This allows a good efficiency in less than 10 minutes. It has been shown that low doses of sufentanil (strong opioid) in spinal anesthesia could potentiate the effect of the local anesthetic.

Compare the results of obstetric analgesia by sequential combined spinal epidural with local anesthetic injection associated with morphine and a sequential obstetric analgesia by sequential combined spinal epidural with local anesthetic injection alone

Inclusion Criteria:

• pregnant patients
• patients who experienced a physiological course of pregnancy
• patients for which it was estimated eutrophic fetus without pathology found during ultrasound
• patient consenting to participate to the study
• patient enrolled in the national healthcare insurance program
• patient older than 18 years and younger than 40 years

Exclusion Criteria:

• twin pregnancy
• contraindication to sequential combined spinal epidural