Nazir 2012.

Study characteristics
Methods	RCT
Participants	100 women Inclusion criteria: ASA grade I women undergoing elective CS under spinal anaesthesia with a normal singleton pregnancy beyond 36 weeks' gestation Exclusion criteria: pregnancy‐induced hypertension, diabetes, cardiovascular or cerebrovascular disease, fetal abnormalities, contraindication to spinal anaesthesia Setting: India
Interventions	Prophylactic ephedrine versus phenylephrine Group 1: prophylactic bolus of ephedrine 10 mg IV 1 min after intrathecal injection Group 2: prophylactic dose of phenylephrine 100 μg IV 1 min after intrathecal injection All women received standardised premedication, a standardised fluid preload, a standardised spinal anaesthetic technique (in either lateral or seated position) and dose, standardised surgical positioning. Hypotension managed with rescue boluses of ephedrine 5 mg IV (group 1) or phenylephrine 50 μg IV (group 2) whenever maternal SBP was recorded as less than 90 mmHg. Bradycardia was treated with atropine 300 μg IV bolus.
Outcomes	Maternal: BP (systolic, diastolic, mean); heart rate; need for rescue bolus(es); need for atropine Neonatal: Apgar scores at 1 min and 5 min; umbilical cord blood pH (unclear as to venous or arterial); results for Apgar and pH < 7.2
Notes	Definition of hypotension is a SBP measurement < 90 mmHg. Bradycardia was defined as heart rate < 60 bpm.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"Randomly allocated into two groups of 50 each" – method not specified
Allocation concealment (selection bias)	Unclear risk	"Randomly allocated into two groups of 50 each" – method not specified
Blinding of participants and personnel (performance bias) All outcomes	Low risk	"Double blind" – the vasopressor solutions were prepared in identical syringes by an anaesthetist or investigator who was not involved in subsequent patient care
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Not reported, but outcomes probably recorded by staff involved in care
Incomplete outcome data (attrition bias) All outcomes	Low risk	No losses reported
Selective reporting (reporting bias)	Low risk	Most expected outcomes reported
Other bias	Low risk	None evident