Yanny 2000.
| Methods | RCT. | |
| Participants | Inclusion criteria: women with breech presentation choosing ECV, cardiotocograph and US examination acceptable, failed initial ECV attempt without tocolysis. N = 57. | |
| Interventions |
Intervention:tocolytic: glycerol trinitrate/nitroglycerine ‐ nitric oxide donor (A3) ‐ sublingual. Glyceryl trinitrate sublingual spray 800 µg. N = 31. Comparison:placebo. N = 26. Labelled sprays A and B; repeat ECV attempt; if unsuccessful and uterus not relaxed, salbutamol infusion and repeat ECV attempt. |
|
| Outcomes | Side effects: maternal discomfort; blood pressure; pulse, after spray administration; ECV success; uterine relaxation (poor 8/30 nitroglycerine vs 9/25 placebo, reasonable 11/30 vs 8/25, good 7/30 vs 8/25, excellent 4/30 vs 0/25); salbutamol required (13/31 vs 14/26); dose of salbutamol. | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Computer‐generated random numbers. |
| Allocation concealment (selection bias) | Low risk | Used opaque sealed envelopes, but no information as to whether they were sequentially numbered. |
| Blinding of participants and personnel (performance bias) All outcomes | Unclear risk | No information provided. |
| Blinding of outcome assessment (detection bias) All outcomes | Unclear risk | No information provided. |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | No exclusions were reported after randomisation, and no loss to follow‐up. |
| Selective reporting (reporting bias) | Unclear risk | We did not assess the trial protocol. |
| Other bias | Low risk | Baseline characteristics for the women were similar between the 2 groups in maternal age, parity, extended legs and liquor volume. No other biases were apparent. |
AFI: amniotic fluid index. BMI: body mass index. CI: confidence interval. CS: caesarean section. CSE: combined spinal epidural. CTG: cardiotocography. ECV: external cephalic version. EFW estimated fetal weight. GA: gestational age. IUGR: intrauterine growth restriction. IV: intravenous. IVI: intravenous infusion. min(s): minute(s). NST: non‐stress test. OR: odds ratio. RCT: randomised controlled trial. SD: standard deviation. SQ: subcutaneous. US: ultrasound. vs: versus.
A: Tocolytic drugs: A1 ‐ beta stimulants; A2 ‐ calcium channel blockers; A3 ‐ nitric oxide donors. B: Vibroacoustic stimulation. C: Regional analgesia. D: Amnioinfusion. E: Systemic opioids.