Effect of calcium injection on adequacy of uterus to return to normal muscle tone and thus stop bleeding during surgery for baby delivery

INTERVENTION: Intervention1: Calcium group: Calcium chloride therapy.: Will receive 10 ml of 10 percent calcium chloride intravenously, diluted with 40 ml of normal saline such that total volume is 50 ml.The study drug will be administered over 5 minutes starting at umbilical cord clamping via infusion pump at rate of 10 ml per min. Control Intervention1: Placebo: Normal saline: Will receive normal saline infusion in total volume of 50 ml.The infusion will be administered over 5 minutes starting at umbilical cord clamping via infusion pump at rate of 10 ml per min. CONDITION: Health Condition 1: O720‐ Third‐stage hemorrhage PRIMARY OUTCOME: Incidence of additional uterotonic drug requirement despite the oxytocin injection, during the surgery.Timepoint: During period starting from end of oxytocin injection to end of surgery. SECONDARY OUTCOME: Blood lossTimepoint: At end of surgery. INCLUSION CRITERIA: Women with preeclampsia scheduled for intrapartum caesarean delivery, defined as labor with or without oxytocin administration prior to cesarean delivery, using spinal anaesthesia.