Another measure will be taken after delivery of the fetus. SAB will be done in sitting position under complete asepsis using 25 g spinal needle with crystalloid infusion of 500 mL. SAB will be achieved by intrathecal injection of 10 mg hyperbaric Bupivacaine plus 25ug fentanyl. Success of SAB will be tested within five minutes after drug injection. SAB will be considered successful if adequate block reached T4 dermatome.