Niu 2018.

Study characteristics
Methods	RCT
Participants	Women having elective CS under spinal anaesthesia N = 80 women randomised and their data analysed
Interventions	Intervention: sedative ( Comparison 6) Propofol – 10 mg/mL continuous infusion. (aiming at a plasma concentration of 1000 ng/mL)· Given after the birth· N = 40 Comparator: placebo N =40
Outcomes	Nausea and vomiting
Notes	Setting: Aviation General Hospital, Beijing, China Dates: October 2016 to February 2017 Funding source: not reported Declaration of interest: stated that authors have no conflicts of interest Authors also reported on maternal pain and neonatal behavioral neurological assessment (NBNA), reporting no difference between the groups
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"random number generator"
Allocation concealment (selection bias)	Unclear risk	Quote: “Allocated using random number by research fellow A 1:1 ratio – who was not involved with assessment or pt instructions (that was RF B). After obtaining consent, patients were allocated to either the propofol or the placebo group by opening a sealed opaque envelope.” However, it is unclear if the envelopes were sequentially numbered.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "The parturient head site was covered by surgical drapes during the operation so they could not see the infusion line.”
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Assessed by independent Research Fellow that was not involved with randomisation – different research fellows assessed different outcomes
Incomplete outcome data (attrition bias) All outcomes	Low risk	All included in the analysis. 92 women were scheduled for CS – 12 were excluded, the remaining 80 women completed the trial
Selective reporting (reporting bias)	Unclear risk	All outcomes from the methods section were reported on but we did not assess the trial protocol..
Other bias	Unclear risk	It is not clear if there may have been other biases