Preventive Intramuscular Phenylephrine in Elective Cesarean Section Under Spinal Anesthesia

5 mg (1ml) phenylephrine intramuscular injection will be given into the gluteus maximus muscle before anesthesia.100ug (1ml) phenylephrine intravenous injection will be given after the subarachnoid injection is completed .

1ml 0.9% normal saline intramuscular injection will be given into the gluteus maximus muscle before anesthesia and after the subarachnoid injection is completed.

All patients will receive spinal anesthesia with bupivacaine.