The analgesic efficacy of subarachnoid morphine in comparison with ultrasound-guided transversus abdominis plane block after cesarean delivery: a randomized controlled trial
ASA physical status I or II parturients, scheduled for elective cesarean delivery, via a Pfannenstiel incision, under spinal anesthesia
body mass index >35 kg/m2, major systemic disease, chronic pain disorders, abuse of drugs or alcohol, and allergies to any medication included in the study protocol