This prospective, assessor-blinded observational cohort study will investigate the effect of adding bilateral ultrasound-guided transversus abdominis plane (TAP) block to standard intrathecal morphine (ITM) analgesia on the quality of recovery in women undergoing elective cesarean delivery under spinal anesthesia. All participants will receive ITM as part of routine spinal anesthesia. The TAP group will receive an additional bilateral ultrasound-guided TAP block at the end of surgery, while the control group will not receive any additional block. Both groups will receive standardized postoperative analgesia with intravenous patient-controlled analgesia (IV PCA). The primary outcome is the quality of recovery at 24 hours postoperatively, measured using the validated Obstetric Quality of Recovery-10 (ObsQoR-10) questionnaire. Secondary outcomes include Numerical Rating Scale (NRS) pain scores, time to first breastfeeding, time to mobilization, time to hospital discharge, and total opioid consumption in the first 24 hours after surgery. Outcome assessors will be blinded to group allocation. The study aims to determine whether TAP block enhances functional recovery, reduces pain, and decreases analgesic requirements when used alongside ITM in cesarean delivery patients.

Effective postoperative analgesia is essential for optimizing maternal recovery after cesarean delivery, promoting early mobilization, and supporting breastfeeding initiation. Spinal anesthesia with intrathecal morphine (ITM) is commonly used due to its long-lasting analgesia; however, it may not provide complete abdominal wall analgesia and can be associated with opioid-related side effects. The transversus abdominis plane (TAP) block is an ultrasound-guided regional anesthesia technique that provides somatic analgesia to the anterior abdominal wall by targeting the anterior rami of the thoracolumbar spinal nerves (T6-L1). When combined with ITM, TAP block may further improve recovery quality, reduce opioid requirements, and facilitate earlier return to daily activities.

In this prospective, assessor-blinded observational cohort study, all eligible patients undergoing elective cesarean delivery under spinal anesthesia at our institution will receive ITM as part of standard practice. Participants will be managed in two groups based on postoperative analgesia:

• TAP Group: Bilateral ultrasound-guided TAP block performed at the end of surgery in addition to ITM.
• Control Group: ITM only, without additional regional block.

Both groups will receive standardized postoperative analgesia via intravenous patient-controlled analgesia (IV PCA). Data will be collected prospectively, and the outcome assessor responsible for postoperative evaluation will be blinded to group allocation.

Primary Outcome:

• Quality of recovery at 24 hours postoperatively, measured using the Obstetric Quality of Recovery-10 (ObsQoR-10) questionnaire.

Secondary Outcomes:

• Numerical Rating Scale (NRS) pain scores
• Time to first breastfeeding
• Time to first mobilization
• Time to hospital discharge
• Total opioid consumption within the first 24 hours

By analyzing these parameters, the study aims to clarify whether the addition of TAP block to ITM-based analgesia can enhance recovery quality, improve functional outcomes, reduce pain intensity, and decrease opioid consumption in cesarean delivery patients. Findings from this research could inform best practice guidelines for postoperative pain management in obstetric anesthesia.

Inclusion Criteria:

• Female patients aged 18-45 years
• Singleton pregnancy
• ASA physical status II-III
• Scheduled elective lower segment cesarean delivery under spinal anesthesia with intrathecal morphine (ITM) as standard care
• Able to understand study procedures, provide written informed consent, and reliably use IV PCA
• Able to complete ObsQoR-10-T assessments (with trained assistance if needed)

Exclusion Criteria:

• Contraindication to spinal anesthesia or TAP block (e.g., infection at injection site, coagulopathy, allergy to local anesthetics)
• Chronic opioid use or opioid/alfa-2 agonist intolerance
• Severe preeclampsia, HELLP syndrome, significant hepatic or renal impairment
• Urgent or emergent cesarean section (Category 1)
• Cognitive impairment or communication difficulty preventing accurate assessment
• Prior major abdominal surgery (other than previous cesarean delivery)
• Body mass index (BMI) > 40 kg/m²
• Major psychiatric illness (e.g., major depressive disorder, generalized anxiety disorder, psychosis) that may affect pain perception or quality of recovery

Women undergoing elective cesarean delivery under spinal anesthesia with intrathecal morphine at a tertiary university hospital. Two observational cohorts will be followed: one receiving only intrathecal morphine and the other receiving intrathecal morphine plus bilateral ultrasound-guided TAP block.

De-identified individual participant data (IPD), data dictionary, and statistical analysis code will be shared with qualified researchers upon reasonable request, after publication of the main results. Data will be available 12 months after study completion and for up to 5 years. Requests must be accompanied by a methodologically sound proposal and relevant ethics approval.

IPD and supporting information will be available beginning 12 months after the study's completion date and remain available for 5 years.

Qualified researchers affiliated with academic institutions or research organizations, who provide a methodologically sound proposal and relevant ethics approval, may request access. Requests will be reviewed by the principal investigator. Approved researchers will receive access to de-identified datasets and related documentation via secure institutional data sharing platforms.