Collaris 2009.

Methods	RCT.
Participants	Inclusion criteria: woman not in labour, with singleton pregnancy in breech or transverse lie at 36 to 41 weeks' gestation. N = 90. Exclusion criteria: in keeping with recommendations of the American College of Obstetricians and Gynecologists on ECV.
Interventions	Intervention:tocolytic: nifedipine ‐ calcium channel blocker (A2) ‐ oral. Oral nifedipine (10 mg) and SQ saline placebo. N = 44. Comparison:tocolytic: terbutaline ‐ beta stimulant (A1) ‐ parenteral. Subcutaenous terbutaline (250 micrograms) with oral placebo. N = 46.
Outcomes	Primary outcomes were successful ECV and CS. Secondary outcomes were cephalic fetal presentation at delivery, numerical rating score for satisfaction with ECV, preference for injection or tablet, post ECV. Also, CTG assessment, labour onset, prelabour membrane rupture and various neonatal outcomes.
Notes	Women who had a failed ECV on first attempt could be re‐randomised. Study authors did a primary analysis on 90 women, but then undertook a secondary analysis by adding in repeat ECV attempts. We will consider only the primary analysis data.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated, variable blocks of 8 or 12.
Allocation concealment (selection bias)	Low risk	No indication that this was an issue; did use sequential opening of sealed opaque envelopes.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Participants and providers blinded; unclear whether outcome assessor was blinded.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Participants and providers blinded; unclear whether outcome assessor was blinded.
Incomplete outcome data (attrition bias) All outcomes	Low risk	For some outcomes, data were collected only for a subset of participants; CTGs of 7 women (7%) were missing from the files. Analysis of participants at primary enrolment was performed on an intention‐to‐treat basis. All women received treatment as allocated.
Selective reporting (reporting bias)	Unclear risk	We did not assess the trial protocol.
Other bias	Low risk	No significant differences were noted in baseline criteria; no other biases were apparent.