Ozkan 2004.

Study characteristics
Methods	RCT
Participants	150 women Inclusion criteria: absence of any systemic illness or fetal pathology, undergoing CS under spinal anaesthesia
Interventions	Crystalloid preload versus colloid preload versus crystalloid preload + prophylactic ephedrine versus colloid preload + prophylactic ephedrine Group1: Ringer's lactate IV 1000 mL Group 2: Ringer's lactate IV 1000 mL + ephedrine 15 mg Group 3: Ringer's lactate IV 1000 mL + ephedrine 30 mg Group 4: gelatine 500 mL solution Group 5: gelatine 500 mL + ephedrine 15 mg Group 6: gelatine 500 mL + ephedrine 30 mg Unclear whether standardised spinal anaesthetic technique and dose Hypotension treated with additional Ringer's lactate infusions while hypotensive periods longer than 3 min were treated with 5 mg ephedrine IV
Outcomes	Maternal: hypotension; heart rate; nausea; vomiting; vasopressor requirement Neonatal: stated that there were no significant differences in neonatal outcomes, but these outcomes were not described
Notes	Hypotension defined as < 20% of baseline
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method not described
Allocation concealment (selection bias)	Unclear risk	Method not described
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Blinding not stated
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Blinding not stated
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Losses to follow‐up not stated
Selective reporting (reporting bias)	Unclear risk	Not apparent, but not well reported
Other bias	High risk	Variable dose of local anaesthetic used for spinal anaesthesia