Pregnant women scheduled for elective cesarean sections under spinal anesthesia are randomly assigned to two groups: 1) the Fentanyl-Morphine (FM) group, and 2) the Morphine (M) group. In addition to 11.5 mg of bupivacaine, the FM group receives 15 μg of fentanyl and 50 μg of morphine intrathecally, while the M group receives 50 μg of morphine intrathecally. The incidence of intraoperative pain with a Numerical Rating Scale (NRS) score of 4 or higher is compared between the two groups to evaluate the analgesic effects of combined intrathecal fentanyl-morphine therapy versus morphine alone.
Parturients of gestational age > 37 weeks, scheduled for cesarean section under spinal anesthesia
Contraindication to spinal anesthesia
Any sign of onset of labor
Emergency cesarean section
Body weight < 40 kg or > 120 kg