Level 2: Mid-level evidence
In an assessment of electronic fetal monitoring during labor, a systematic review of 12 randomized and quasi-randomized trials evaluated continuous cardiotocography in more than 37,000 women (Cochrane Database Syst Rev. 2006:CD006066). Only two of the trials were of high quality. The review was dominated by one well-done trial with nearly 13,000 women.
There was no significant difference in the rates of overall perinatal death (relative risk 0.85, 95% confidence interval [CI] 0.59-1.23) in 11 trials with 33,513 patients. Continuous cardiotocography was associated with a possible increase in cerebral palsy (relative risk 1.74, 95% CI 0.97-3.11) in two trials with 13,252 patients, but this finding was not statistically significant. In addition, cardiotocography was associated with a decreased rate of neonatal seizures (relative risk 0.5, 95% CI 0.31-0.8) in nine trials with 32,386 patients and an increased rate of instrumental vaginal birth (relative risk 1.16, 95% CI 1.01-1.32) in nine trials with 18,151 patients.