The study includes all women who have delivered vaginally . Quantification of blood loss is done by making a list of  dry weights for delivery items that may become blood soaked with directions on how to calculate blood loss.  Quantification of blood loss is begun immediately after the infant’s birth (before delivery of the placenta) and  the amount of fluid collected in a calibrated under-buttocks drape is assessed and recorded. Most of the fluid collected before delivery of the placenta is amniotic fluid, urine, and feces. If irrigation is used, the amount of irrigation from the total fluid that was collected is subtracted. The total volume of fluid collected in the under-buttocks drape is recorded. The preplacental fluid volume is subtracted from the post placental fluid volume to more accurately determine the actual blood loss. Most of the fluid collected after the delivery of the placenta is blood. The fluid volume collected in the drapes is added to the blood volume measured by weighing soaked items to determine the cumulative volume of blood loss or quantification of blood loss. All blood-soaked materials and clots are weighed to determine cumulative volume. 1 gram weight=1 milliliter blood loss volume. The equation* used when calculating blood loss of a blood-soaked item is WET Item Gram Weight - DRY Item Gram Weight=Milliliters of Blood Within the Item.. [10, 11, 12]

Randomized controlled trials with outcome measure of blood loss ≥500ml are eligible if they compared carbetocin with oxytocin to prevent postpartum hemorrhage during prophylaxis of PPH in women following vaginal delivery. The primary outcome is blood loss of at least 500ml after vaginal delivery. The secondary outcomes will be blood loss of at least 1000ml; use of additional uterotonic agents; blood transfusion; uterine massage; flushing; vomiting; abdominal pain; nausea; dizziness; headache; palpitation; itching; shivering.

Side-effects are also an important concern when choosing uterotonic agents. Although carbetocin seems to be an ideal agent compared to other uterotonic agents, some side-effects, such as vomiting, nausea, and dysarteriotony, are still concerning. Side-effects are also considered as secondary outcomes in these trials. Clinicians do not fully understand the side-effects of carbetocin to PPH, particularly the unanticipated ones. There seems to be a gap in the detailed presentation of the side-effects of carbetocin. Therefore, this study also aims to assess the side-effects of  carbetocin compared to oxytocin in the prevention of PPH

Carbetocin 100mcg IV will be administered without any other confounding factor to subjects and then compared with the subjects who have been administered oxytocin 10IU with additional uterotonic agents.