Inclusion Criteria:  Adult full-term parturients scheduled to undergo elective cesarean delivery under spinal anesthesia  Exclusion Criteria:  Contraindication to spinal anesthesia Any chronic pain unrelated pregnancy current opioid medication use BMI more than 40 kg m-2 History of drug allergy or hypersensitivity to fentanyl, morphine, ropivacaine, acetaminophen, NSAIDs, bupivacaine, ramosetron, ondansetron, nalbuphine, Naloxone, metoclopramide infection of abdominal wall Pregnancy-induced hypertension known cardiovascular disease Known fetal anomaly Any sign of onset of labor