In this sub-analysis of the Dutch randomised trial it is shown that cases with adverse outcome in the index group (CTG+ST analysis) could have been avoided by stricter adherence to Stan guidelines. Improved CTG interpretation and timing of fetal blood sampling could have led to better outcomes in the control group.
Recordings of neonates with adverse outcome from the trial were independently assessed by experienced obstetricians. They were asked to judge whether or not there had been an indication to intervene for suspected fetal distress. The assessment included CTG interpretation, result of FBS, significant ST Events and adherence to the study protocol with respect to correct and timely intervention. In total 59 cases were assessed by the experts.
Correct fetal indication to intervene was assessed by the experts in 23 of 26 (88.5%)cases in the index group and in 19 0f 33 (57.6%) cases in the control group.
The number of cases in which the interval between intervention and birth exceeded 20 minutes was 13 (50%) in the index group and 11 (33%) in the control group. The experts judged protocol violations in 11 (42.3%) and 13 (39.4%) cases respectively.
Correct adherence to study protocol leading to better outcome was judged by the experts as follows:
If the study protocol had been correctly followed, monitoring with ST analysis in combination with CTG would have detected almost 90% of cases with adverse outcome while CTG in combination with fetal blood sampling could have detected only 60%.
The authors conclude that the results indicate that monitoring by ST analysis is more specific and comprehensive regarding the aim to detect and deliver compromised fetuses than monitoring by CTG only. A strict adherence to clinical guidelines, especially with respect to correct classification of the CTG, could lead to additional identification and prevention of cases with adverse outcome. This may potentially improve the overall effectiveness of fetal monitoring by ST analysis of the fetal ECG.