Wang 2014a.

Study characteristics
Methods	RCT
Participants	150 women Inclusion criteria: primiparous, single fetus, elective caesarean, age 18‐35 years, 37‐40 weeks gestation, ASA I‐II, normal prenatal exam, normal liver and renal function, normal fetal screening, no medical history of heart or lung disease Setting: China
Interventions	Comparison of different doses of prophylactic ondansetron versus control 5 min prior to spinal anaesthesia, women were given (all diluted to 5 mL with physiological saline): Group 1: 5 mL physiological saline Group 2: 2 mg ondansetron Group 3: 4 mg ondansetron Group 4: 6 mg ondansetron Group 5: 8 mg ondansetron All women received no premedication, routine monitoring, cannulation, a standardised crystalloid coload, and a standardised spinal anaesthetic technique and dose Treatment of hypotension consisted of administration of IV bolus of 100 μg phenylephrine
Outcomes	Maternal: hypotension, treatment for hypotension/bradycardia, nausea and vomiting Neonatal: cord gases, Apgar score at 1 min and 5 min
Notes	Hypotension defined as systolic pressure < 80% of baseline
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated codes
Allocation concealment (selection bias)	Unclear risk	Not mentioned
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Ondansetron and saline solutions were prepared by an anaesthetist who was blinded to this study.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	As above
Incomplete outcome data (attrition bias) All outcomes	Low risk	None reported
Selective reporting (reporting bias)	Low risk	None apparent
Other bias	Low risk	None apparent