A Cochrane review included 6 studies with a total of 2105 women, all at increased risk of complications. Comparison of traditional cardiotocography (CTG) versus no CTG showed no significant difference in perinatal mortality (2.3% vs 1.1%; RR 2.05, 95% CI 0.95 to 4.42; 4 trials, n = 1627) or potentially preventable deaths (RR 2.46, 95% CI 0.96 to 6.30; 4 trials; n = 1627, though the meta-analysis was underpowered to assess this outcome). Similarly, there was no significant difference in caesarean sections (RR 1.06, 95% CI 0.88 to 1.28; 3 trials, n = 1279) nor in the secondary outcomes that were assessed. No studies compared computerised CTG with no CTG. Perinatal mortality was reduced with use of computerised CTG compared with traditional CTG (0.9% vs 4.2%, RR 0.20, 95% CI 0.04 to 0.88; 2 trials, n=469). However, there was no significant difference identified in potentially preventable deaths (RR 0.23, 95% CI 0.04 to 1.2), though the meta-analysis was underpowered to assess this outcome.
Comment: The quality of evidence is downgraded by several shortcomings in study quality and by imprecise results for clinically important outcomes.