To compare the efficacy and safety profile of intravenous tranexamic acid versus intrauterine misoprostol in reducing the blood loss during and after cesarean delivery in pregnant women diagnosed with placenta previa

Placenta previa is defined as complete or partial covering of the internal os of the cervix with the placenta, at more than 16 weeks of gestation. It affects 0.3% to 2% of pregnancies in the third trimester and has become more evident secondary to the increasing rates of cesarean delivery (CD).

Placenta previa is a major risk factor for postpartum hemorrhage (PPH) and can lead to maternal and neonatal morbidity and mortality. Uncontrolled PPH from placenta previa may necessitate blood transfusion, hysterectomy, admission to the intensive care unit, or even death.

The efficacy of routine administration of oxytocin, to reduce the frequency of PPH after vaginal and cesarean birth is well-established. The Royal College of Obstetricians and Gynecologists recommends a slow IV bolus dose of 5 IU of oxytocin after delivery of the neonate in CD to ensure adequate uterine contractility, reduce intraoperative blood loss and prevent PPH. Likewise, the American College of Obstetricians and Gynecologists recommends the practice to use oxytocin but infusion instead of a bolus dose. Regardless of the mode of administration, oxytocin use in the setting of CD may result in maternal adverse effects, such as hypotension and tachycardia.

Misoprostol, a prostaglandin E1 analogue with strong uterotonic properties binds to myometrial cells to cause strong myometrial contractions. Misoprostol has been suggested as an alternative to injectable uterotonic agents for preventing PPH following vaginal or CD. It can be used orally, sublingually, buccally, rectally or put intrauterine with similar efficacy as oxytocin in reducing blood loss, preventing and treating PPH. Because of its availability, low cost, thermal stability, and ease of administration, misoprostol is suitable for worldwide use even in low resource settings in developing countries.

Tranexamic Acid (TA) is an analogue of lysine that inhibits fibrinolysis by competitively binding to plasminogen. It prevents the lysis of formed clot by inhibiting activation of plasminogen and plasmin. It is ten times more potent than amino-caproic acid. Several studies had assessed the use of TA in both the prophylaxis against and the treatment of PPH with the conclusion that TA reduces the following; blood loss in women with PPH, the need for hysterectomy, the risk of severe anemia and the need for further blood transfusion; hence, this could contribute significantly to the goal of reducing maternal mortality

Inclusion Criteria:

• Parity: primigravida or multigravida.
• Gestational age: ≥ 36 weeks (confirmed by the first day of the last menstrual period or first trimester ultrasound scan).
• Candidate for termination of pregnancy by cesarean delivery.
• Singleton living healthy normally growing fetus.
• Cesarean delivery under spinal anesthesia.
• Pregnancies complicated with placenta previa diagnosed preoperatively by ultrasonography (placenta previa was defined as placenta partially or totally covers the cervix)

Exclusion Criteria:

• Patients diagnosed with morbidly adherent placenta.
• Placenta previa cases requiring cesarean hysterectomy in the primary surgery.
• Patients with preoperative anemia (Hemoglobin <9 gm/dl).
• History of thromboembolic event.
• Known allergy to tranexamic acid or prostaglandins.
• Bronchial asthma or other contraindications of misoprostol.
• Patients with other risk factors of postpartum hemorrhage (e.g., polyhydramnios, fetal macrosomia, uterine fibroid).
• Patients known to have bleeding tendency (e.g., those receiving anticoagulation, patients with thrombocytopenia, factor VIII or IX deficiency or Von Willebrand's disease).
• More than 2 previous cesarean deliveries procedures.
• Prolonged procedure (more than 2 hours from skin incision to skin closure).
• Concomitant maternal medical disorders (either chronic or pregnancy induced)