Najafianaraki 2010.

Methods	Design: double‐blind randomized controlled trial Country: Iran Multisite: no International: no Treatment duration: intraoperative period Follow‐up: 24 hours postoperatively Operative procedure(s): Shirodkar's operation (cervical cerclage) Randomization unit: participants Analysis unit: individual
Participants	120 participants enrolled ASA I to II female participants aged 20 to 40 years undergoing elective cervical cerclage Exclusion criteria included: history of heart disease; pulmonary disease; liver disease; kidney disease; pre‐existing nausea and vomiting. Randomized to: control group (n = 60, 50%); intervention group (n = 60, 50%). Main characteristics of participants: age (mean): control group 26.9 years; intervention group 25.2 years; number of females/males: 120/0.
Interventions	Control: Ringer's lactate 2 mL/kg/hour spent fasting, initiated preoperatively Intervention: Ringer's lactate 2 mL/kg/hour spent fasting, initiated preoperatively; then given Ringer's lactate 10 mL/kg Co‐interventions: none stated
Outcomes	Vomiting was assessed as a dichotomous outcome. Nausea was assessed on an ordinal scale as "mild", "moderate", or "severe". Nausea was also reported as a dichotomous outcome. These outcomes were reported for the cumulative postoperative period up to discharge, which was 14 hours after the operation.
Notes	Trial registration: not stated Funder: not stated A priori sample size estimation: not stated Conducted: dates not stated Declared conflicts of interest: not stated
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomization was completed using a table of random numbers.
Allocation concealment (selection bias)	Low risk	Randomization was completed using a table of random numbers.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	It is not stated that participants or surgical personnel were blind to group allocation.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	It is stated that ward staff were blinded to group allocation, but no outcome assessor is explicitly identified.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No withdrawals were stated.
Selective reporting (reporting bias)	Low risk	All outcomes were reported.
Other bias	Low risk	There were no other sources of bias.