Voigt 2013.

Study characteristics
Methods	RCT
Participants	Inclusion criteria: Women undergoing elective CS under spinal anaesthesia N = 308 women randomised, none excluded after randomisation but we only included 2 groups in our analysis so 147 women were included in our analysis Exclusion criteria:
Interventions	4 groups: Intervention 1 (group 2): 5HT3 antagonist + dopamine antagonist ‐ not used in this review Tropisetron+metoclopramide N = 82 Intervention 2 (group 3): antihistamine+corticosteroid ‐ not used in this review Dimenhydrinate+dexamethasone N = 79 Intervention 3 (group 4): 5HT3 antagonist (Comparison 1) Tropisetron alone, 4mg given after cord clamping N = 71 Comparator (group 1): placebo no prophylaxis N = 76 We include only group 1 (control) and group 4 Tropisetron alone
Outcomes	Nausea and vomiting: intra‐operative; early post‐operative (0–2 hours); late post‐operative (2–24 hours). We include intra‐operative and early post‐operative as per our Methods (data from the earliest time point).
Notes	Setting: Evangelian Deaconry Hospital, Freiburg, Germany. Dates: 2010 to 2012 Funding source: not reported Declaration of interest: authors stated “None of the authors have any financial relationships with commercial companies involved with a product in this study”. We will write to the authors and request data separated into nausea and vomiting and for information on the risk of bias assessments.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomisation method poorly described ("sealed envelopes")
Allocation concealment (selection bias)	Unclear risk	Although authors report quote: "Sealed opaque envelopes opened by anaesthetist immediately prior to surgery" it is not reported if they were serially numbered.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	No information
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Data collected by quote: "trained investigators"
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	All women appeared to be included in outcome data
Selective reporting (reporting bias)	High risk	Satisfaction and complications do not appear to be reported as per the Methods. We did not assess the trial protocol.
Other bias	Unclear risk	Limited methodological information reported.