Munoz 2014.

Methods	2‐arm RCT. Individual women randomly assigned.
Participants	Dates of data collection: April 2010 to March 2011. Setting: tertiary hospital in Spain with more than 3000 births a year. Inclusion criteria: women with non‐cephalic presentation between 36 and 41 weeks' gestation (All non‐labouring pregnant women at 36 to 41 weeks' gestation with a non‐cephalic presentation confirmed by ultrasound scan were invited to participate). N = 60. Exclusion criteria: fetal abnormalities, intrauterine fetal death, suspicion of fetal growth restriction, fetal weight above 3800 g, maternal cardiovascular disease, American Society of Anesthesiologists class > 2, severe hypertension, allergy to any trial medications, amniotic fluid index < 4 cm, Doppler cerebroplacental ratio > 5th percentile, abnormal cardiotocographic recordings, contraindications to vaginal delivery, uterine abnormalities, coagulation disorders, Rhesus incompatibility, multiple gestation, rupture of membranes and/or placental abruption.
Interventions	Experimental intervention: remifentanil. Remifentanil at 0.1 lg/kg/min, with rescue boluses on demand of 0.1 lg/kg/min and a lockout period of 4 minutes. Given by patient‐controlled pump.All women given IV infusion of ritodrine 200 lg/min for tocolysis. All women given 1 g paracetamol in 100 mL saline (IV) 5 minutes before ECV. N = 31. Control/Comparison intervention: placebo. Study control solution at 0.1 lg/kg/min, with rescue boluses on demand of 0.1 lg/kg/min and a lockout period of 4 minutes. Given by patient‐controlled pump. All women given IV infusion of ritodrine 200 lg/min for tocolysis. All women given 1 g paracetamol (IV) 5 minutes before ECV. N = 29
Outcomes	Pain score (numerical rating scale 0 to 10, no pain to worst pain imaginable); success of ECV; CS; adverse events (nausea, vomiting, dizziness, etc); mode of birth; fetal bradycardia.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	“…computer‐generated random sequence…”.
Allocation concealment (selection bias)	Low risk	Hospital pharmacy prepared 100 mL infusion bags that contained remifentanil (1 mg) or saline, which were labelled with the patient code and sent to the operative room.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Women blind to allocation (placebo‐controlled trial).
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Anaesthesiologists, midwives and obstetricians were blinded to allocation group.
Incomplete outcome data (attrition bias) All outcomes	Low risk	“After randomisation, three women were excluded: two for spontaneous conversion of the fetus to a cephalic presentation, and one who declined to participate”. Obstetric data for 2 further women were lost, but they were included in the statistical analysis on an intention‐to‐treat basis.
Selective reporting (reporting bias)	Low risk	Trial registration form (Valero 2010) lists outcomes, all of which were reported in main study publication (Munoz 2014).
Other bias	Low risk	No imbalance in age; BMI; estimated fetal weight; ethnicity; parity; previous CS; presentation; placenta and amniotic fluid volume.