The Prophylactic Role of Tranexamic Acid in High Risk Pregnant Women Undergoing Elective Cesarean Section in Prevention of Postpartum Hemorrhage

All patients will undergo the following I. History : Medical history, Obstetric history, Comorbidities, Allergies. II. Clinically: Vital signs, Abdomino-pelvic examination, per-vaginal examination. III. Laboratory: Hemoglobin, Hematocrit before \& after cesarean section. IV. Routine Ultrasound. V. Cesarean section: done under spinal anathesia. VI. Calculation of blood loss: The quantity of blood loss (ml) is calculated from 3 components : * (weight of used towels during surgery - weight of used towels prior to surgery),plus * (volume of blood sucked in suction container after placental delivery) ,plus * (weight of used vaginal pad in the first 2 hours after CS - the pad' s dry weight) * Each 1 mg increase the weight of either the towels or the vaginal pads is equivalent to 1 ml blood loss (Vitello, Dominic J., et al). VII. Informed Consent: will be obtained from all participants including the pregnant women who are included in the study . All patients will receive routine ecbolics ( oxytocin ) after delivery of baby.