Pouta 1996.

Study characteristics
Methods	RCT
Participants	22 women Inclusion criteria: healthy women undergoing elective CS at term, indications being breech presentation, contracted pelvis or previous CS Exclusion criteria: multiple gestation, fetal and maternal complications and contraindications to spinal anaesthesia, active labour
Interventions	Colloid preload versus crystalloid preload Group 1: 500 mL 6% HES prior to spinal anaesthesia Group 2: 1000 mL Ringer's lactate prior to spinal anaesthesia All women received standardised aspiration prophylaxis, standardised crystalloid coload, standardised spinal anaesthetic and dose, and standardised surgical positioning.
Outcomes	Maternal: hypotension; data expressed as mean (SD) rather than discrete incidence of hypotension; heart rate; CVP; haematocrit; ANP; endothelin‐1 (ET‐1) assays (central and peripheral); blood loss Neonatal: birthweight; umbilical arterial ANP; ET‐1 assays; pH (expressed as mean (SEM))
Notes	Hypotension defined as SBP < 90 mmHg or less than 80% of baseline
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Methods not described
Allocation concealment (selection bias)	Unclear risk	Methods not described
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Blinding not mentioned
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Blinding not mentioned
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Losses to follow‐up not stated
Selective reporting (reporting bias)	Unclear risk	Unclear reporting
Other bias	Unclear risk	Unclear reporting