Table 3. Perinatal outcomes of breech presentations in the study epochs before and after the introduction of universal 36-week ultrasound scan in St George’s Hospital.
| Outcomes | Before universal ultrasound scan (n = 578) | After universal ultrasound scan (n = 251) | RR (95% CrI), flat prior* | Posterior probability of adverse event reduction | RR (95% CrI), informative prior† | Posterior probability of adverse event reduction |
|---|---|---|---|---|---|---|
| Term breech presentations that were undiagnosed, n (%) | 82 (14.2) | 7 (2.8) | 0.26 (0.10, 0.59) | 99.8% | 0.29 (0.20, 0.38) | >99.9% |
| NNU admission, n (%) | 11 (1.9) | 3 (1.2) | 0.55 (0.12, 1.98) | 79.7% | 0.84 (0.55, 1.28) | 78.0% |
| HIE, n (%) | 2 (0.3) | 1 (0.4) | 1.19 (0.10, 25.1) | 44.8% | 0.32 (0.05, 1.77) | 89.5% |
| Apgar <7 at 5 minutes, n (%) | 11 (1.9) | 2 (0.8) | 0.35 (0.06, 1.42) | 89.8% | 0.23 (0.14, 0.38) | >99.9% |
| Extended perinatal mortality, n (%) | 2 (0.3) | 0 (0.0) | NE | – | 0.21 (0.01, 3.00) | 85.1% |
*Weakly informative priors (N~μ,σ) for population mean and (Student t, df = 3) model intercept.
†Informative priors (N~μ,σ) for population mean was derived from Salim and colleagues and a weakly informative prior (Student t, df = 3) for model intercept.
CrI, credible interval; HIE, hypoxic ischemic encephalopathy; NE, not estimable; NNU, neonatal unit; RR, relative risk.