The transversus abdominis plane block (TAP block) has effect to postoperative analgesia for cesarean section with spinal anesthesia but it was limited for cesarean section with general anesthesia. The hypothesis that this technique has effect to postoperative analgesia for cesarean section with general anesthesia and it could reduce 50% of total morphine consumption during 24 hours after surgery.

This is a randomized, controlled, no-blind clinical trial. The investigators selected 60 cases, who were cesarean section under general anesthesia, age from18 years, and American Society Anesthesiologists (ASA) classification was from II-III. The cases of acute fetal impairment, local anesthesia contraindication, tolerance opioids, liver failure, renal failure, and spinal anesthesia failure were excluded. All cases were randomized assigned two groups: the TAP block group (T group) and controlled group (C group). Each group has 30 cases. The TAP block was performed under the ultrasound guidance with 0.25% of ropivacaine 20 ml each side. The both groups was treated postoperative analgesia with intravenous morphine to patients controlled analgesia (PCA). The primary outcome was total morphine consumption during 24 hours after surgery. The secondary outcomes were the time of required the first dose of morphine, pain score, the complications of TAP block, the side effects of morphine, and satisfaction score of participants. Data was described and analyzed with SPSS 25.0. The sample size was calculated with the hypothesis that TAP block could reduce 50% of dose morphine during 24 hours after surgery, 80% of power, 10% of loss, and 0.05 of alpha error.

Inclusion Criteria:

• Cesarean section with general anesthesia.
• The ASA classification was from II to III

Exclusion Criteria:

• The acute fetal impairment.
• The severe live or renal failure.
• Tolerance opioids

Participants were cesarean section with general anesthesia