Background
nausea, vomiting, hypotension, PPH, uterine atony
POSTPARTUM HAEMORRHAGE, UTERINE ATONY
Postpartum haemorrhage (PPH) continues to be a significant contributor to maternal mortality. Oxytocin has been commonly used for the prevention of PPH. The optimal dosage and administration method of oxytocin utilized in clinical practice remains uncertain. In the past, 5 international unit (IU) oxytocin used to be a reasonable dose for preventing uterine atony [In the prevention or treatment of post-spinal hypotension, prophylactic phenylephrine administration as an infusion has shown superior efficacy to its bolus administration. This is because its use is associated with lower incidence of hypotension, nausea, and vomiting [In the current study, we aimed to determine the 90% effective dose (ED90, the effective dose that prevents uterine atony in 90% of patients) of oxytocin for infusion during cesarean delivery in patients receiving prophylactic phenylephrine. Our hypothesis was that the oxytocin infusion rate would be higher in patients receiving prophylactic phenylephrine than the rate recommended by the international consensus statement [