It will be a prospective observational cohort study. The investigators will compare post-cesarean section recovery in patients receiving intravenous infusion of tramadol-ondansetron versus epidural catheter with infusion of local anesthetics.

The primary outcome is to assess the non-inferiority in terms of post-cesarean section recovery of the intravenous perfusion of tramadol + ondansetron compared to the perfusion of local anesthetics through an epidural catheter.

This will be a prospective observational cohort study, with a total N of 312 patients who underwent a cesarean section. 156 who maintain the epidural catheter as the main measure of analgesia for 24 h, and 156 who receive an infusion of tramadol-ondansetron from the end of the cesarean section and for the following 24 h. The following data will be collected at 24 and 48 hours: need for unscheduled pharmacological reinforcement, adverse effects, QoR (Quality of Recovery) score 15, ObsQor-10 (Obstetric Quality of Recovery) score, and Visual Analogue Pain Scale (VAS) every 4 hours for 48 hours. The incidence of chronic pain 90 days after cesarean section will be assessed using the Numerical Pain Rating Scale (NRS).

Inclusion Criteria:

• Woman over 18 years old undergoing caesarean section
• She agrees to participate voluntarily.
• She is already receiving any of the analgesic strategies studied.

Exclusion Criteria:

• Receiving an analgesic medication other than the one mentioned as "routine multimodal analgesia" (either as regular medication or for acute post-surgical pain)
• Medical history that determines the baseline data of the scales and data that we collect ( pain or previous disabilities; addiction to drugs, alcohol or drugs; another disease that worsens the quality of life)
• Medical history that conditions the pharmacological effect (allergy, intolerance or atypical reaction to any of the drugs involved in its treatment or possible cross-reactions )
• Contraindication for neuraxial techniques (patient refusal, difficulty in understanding or communication, localized infection, increased intracranial pressure, or other medical criteria)
• Two or more previous caesarean sections
• Difficulty in understanding or communication
• Mother care will not be available to the newborn in the postpartum period for any reason

The target population of this study would correspond to women who underwent a caesarean section (therefore, of childbearing age) in the first 48 hours of their puerperium, who underwent surgery at the HUiP La Fe. Among these, the patients who, following the practice usual clinical presentation in a standard cesarean section at the study center, receive a TRON or an infusion through the epidural catheter with ropivacaine.