Karinen 1995.

Study characteristics
Methods	RCT
Participants	26 women Inclusion criteria: term parturients undergoing elective CS, healthy, uncomplicated singleton, non‐labouring
Interventions	Colloid versus crystalloid preload Group 1: 500 mL 6% HES Group 2: 1000 mL Ringer's lactate Study drug infused over 10 min prior to spinal anaesthesia All women received standardised aspiration prophylaxis, standardised spinal anaesthetic technique and dose and standardised crystalloid infusion after spinal anaesthetic.
Outcomes	Maternal: hypotension; uterine artery pulsatile index; CVP; induction‐delivery time Neonatal: Apgar scores at 1 min, 5 min, and 15 min (incomplete data); umbilical artery pH (expressed as mean and range)
Notes	Hypotension defined as SBP < 80% baseline or < 90 mmHg
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	"Sealed envelopes" – no further details provided
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Blinding: obstetrician performing ultrasound blinded to allocation, other blinding not mentioned
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	As above
Incomplete outcome data (attrition bias) All outcomes	Low risk	Losses to follow‐up: none
Selective reporting (reporting bias)	Unclear risk	Not reported
Other bias	Low risk	Not apparent