Background: Post-spinal hypotension is a common complication with incidence as high as 30-90%. This may lead to adverse maternal and foetal outcomes such as nausea, emesis, light headedness, impair uterine and intervillous blood flow, and result in foetal acidosis and neonatal depression. The aim of this study is to compare bolus doses of Phenylephrine and Norepinephrine for treating hypotension in mothers undergoing elective caesarean section under spinal anaesthesia.

Methods: Eight-six pregnant mothers with singleton pregnancy posted for caesarean section will be randomly assigned to either Phenylephrine group or a Norepinephrine group. An assessor blind to group allocation will measure umbilical artery pH obtained from blood samples sent for blood gas analysis from a segment of umbilical cord double clamped before the baby’s first breath, Apgar scores at 1 min and 5 min, birth weight, the number of hypotensive episodes, vasopressor requirements, the incidence of tachycardia/bradycardia/ arrhythmias/hypertension and maternal complications such as nausea and vomiting, and shivering. It is hypothesized that Phenylephrine has better neonatal and maternal outcomes, and has better efficacy in treating hypotension when compared to Norepinephrine.

Discussion: If the study proves that Norepinephrine is more beneficial vis-a-vis Phenylephrine as vasopressor to maintain blood pressure and cardiac output following spinal anaesthesia, it could lead to increased use of Norepinephrine with benefits to neonatal outcomes and better maternal haemodynamic control.