Marquette 1996.

Methods	RCT.
Participants	Inclusion criteria: women with singleton breech presentation, 36 to 41 weeks' gestation, reactive CTG, breech mobile on abdominal palpation. N = 283. Exclusion criteria: impaired fetal growth (estimated weight < 10th percentile), oligohydramnios (AFI < 5), placenta praevia, placental abruption, uterine scar other than low transverse CS, active labour, ruptured membranes, fetal anomalies incompatible with life, contraindication to vaginal delivery, contraindication to tocolysis.
Interventions	Intervention:tocolytic: ritodrine ‐ beta stimulant (A1) ‐ parenteral. IVI, for 20 minutes before and during ECV attempt, of ritodrine 111 micrograms/min or placebo. Maximum of 3 ECV attempts as forward or backward flip. CTG was repeated. N = 138. Comparison:placebo. N = 145
Outcomes	Duration of infusion (tocolysis mean 32.1 (SD 1.04) vs control 31.7 (1.12) minutes); unsuccessful ECV; CTG results (all reactive); time from ECV to birth (average 2 weeks); maternal and fetal complications (maternal complications < 4%, similar between groups); mode of birth; birthweight (3370 (39) vs 3382 (44) grams).
Notes	Groups differed in terms of frank breech (tocolysis 59/138 vs control 43/145) and nulliparity (58/138 vs 49/145). Parity (nulliparous 34% vs parous 61%), but not type of breech, affected ECV success rate; therefore results controlled for parity.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	States random assignment of every 10 patients enrolled: 5 to ritodrine and 5 to control.
Allocation concealment (selection bias)	Unclear risk	No information provided.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Placebo and treatment made up in pharmacy in identical phials and administered IV in the same solution at the same rate.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Placebo and treatment made up in pharmacy in identical phials and administered IV in the same solution at the same rate.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No exclusions or loss to follow‐up reported.
Selective reporting (reporting bias)	Unclear risk	We did not assess the trial protocol.
Other bias	Unclear risk	Ritodrine group had higher proportion of nulliparous women. It is unclear whether this would impact the comparison of outcomes.