Norepinephrine on Maternal Hypotension After Combined Lumbar and Epidural Anaesthesia

Participants in this arm will receive norepinephrine as a bolus dose to treat maternal hypotension during cesarean section under spinal anesthesia. The dosage will be determined using the upper and lower sequential distribution method (UDM). The aim is to investigate the effective dose (ED50 and ED95) of norepinephrine in maintaining maternal blood pressure stability and optimizing maternal outcomes during the procedure.