Hasan 2012.

Study characteristics
Methods	RCT
Participants	90 women Inclusion criteria: ASA I‐II, age 20‐35 years, weight 45‐60 kg, height 153‐165 cm Exclusion criteria: pregnancy‐induced hypertension, chronic hypertension, pre‐eclampsia, twin pregnancy, fetal compromise, diabetes mellitus, polyhydramnios, renal, liver or heart disease, coagulopathy Setting: Bangladesh
Interventions	Crystalloid preload versus colloid preload versus combination preload Group 1: Ringer's lactate 20 mL/kg preloading Group 2: HES 6% 8 mL/kg preloading Group 3: combination of RL 10 mL/kg and HES 6% 4 mL/kg preloading All women received standardised cannulation, standardised spinal anaesthetic technique and dose, standardised surgical positioning, standardised oxygen therapy and standardised oxytocin dose after delivery Hypotension was treated with IV boluses of ephedrine 5 mg and rapid infusion of Ringer's lactate in all 3 groups
Outcomes	Maternal: systolic, diastolic and mean BP measurements; total dose of ephedrine; total volume of IV fluid given Neonatal: Apgar scores
Notes	Hypotension defined as SBP less than 100 mmHg AND less than 20% of the baseline BP
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Unclear method. "Randomisations were done using card sampling"
Allocation concealment (selection bias)	Low risk	Anaesthetist who generated the random sequence infused the allocated fluid behind a screen set, separate from the outcome assessor.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Participants and outcome assessors were blinded; however, the personnel who generated the random sequence and infused the fluid were not blinded.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	As above
Incomplete outcome data (attrition bias) All outcomes	Low risk	All participants included in final analysis
Selective reporting (reporting bias)	Low risk	None apparent
Other bias	Low risk	None apparent