Placenta previa can have serious adverse consequences for the mother, including an increased risk of maternal mobility, antenatal and intrapartum hemorrhage, and the mother may, therefore, require a blood transfusion or even an emergency hysterectomy. Although it is a relatively rare condition with an overall incidence of 0.28-2.0% of all deliveries, it has been suggested that the incidence of placenta previa is increasing. Many gynecological surgeons use a local injection of vasopressin, which is a known peripheral vasoconstrictor, at the time of laparoscopic myomectomy to decrease blood loss. In addition, the useful role for local infiltration of vasopressin to arrest hemorrhage from the placental bed has been demonstrated in several obstetrical case reports. The vasopressin V1α receptor has been demonstrated to be present in the myometrium of both non-pregnant and pregnant women and contributes to myometrial contraction. Therefore, the investigators evaluated the effect of local injection of vasopressin on the blood loss and secondary impact on complications during cesarean section in cases of placenta previa.

The study drug was administered immediately after delivery, as soon as the umbilical cord was clamped. The experimental group received a bolus injection of vasopressin (4 IU) diluted to 2 mL with saline into the myometrium of the placental bed during slow (30-seeconds) Conversely, the placebo group received a 10-mL bolus injection of saline into the myometrium during slow (30-seconds).

Inclusion Criteria:

• all pregnant women with a single term fetus scheduled for an elective cesarean section for complete placenta previa and invited them to participate in the study. The placenta previa was defined as a placenta completely covering the cervical os in ultrasound examination

Exclusion Criteria:

• Patients with a cardiac, hepatic, renal or thromboembolic disease.
• patients with the high possibility of the morbid adherent placenta.
• known coagulopathy
• those presented with severe antepartum hemorrhage will be excluded
• hypersensitivity or contraindications of use of vasopressin
• patient refuses to consent

pregnant patients scheduled for cesarean section for placenta previa

The trial will be appropriately blinded; the participants, outcome assessors and the surgeon performing the procedure will be blinded to the medication type, which was used.