ST analysis of the fetal ECG : towards evidence based fetal surveillance

Abstract

It was the aim of this thesis to perform a meta-analysis of published trial on FECG monitoring during labor, to assess its effects on fetal outcome, on the use of FBS, and on instrumental and operative interventions. Furthermore we conducted secondary studies of published data sets to address thus far unresolved issues, such as: are the consensus-based recommendations for additional fetal information effective in preventing fetal acidosis; what is the association between the baseline T/QRS of the FECG (i.e. the T/QRS at the beginning of a recording) and fetal outcome; are biphasic events of the FECG associated with adverse neonatal outcome; what is the effect of maternal fever on the FECG complex; and what is the effect of maternal epidural analgesia on the FECG complex. The first chapter of this thesis describes a meta-analysis comparing ST-waveform analysis of the fetal ECG in combination with cardiotocography (STAN) with continuous cardiotocography alone for several neonatal and maternal outcomes. In this meta-analysis, STAN failed to show a significant reduction in the incidence of metabolic acidosis. Although the meta-analysis did show a significant reduction in the incidence of operative vaginal deliveries with an unaltered incidence of cesarean deliveries. Instrumental vaginal deliveries were reduced with 12% when using STAN. In addition, the meta-analysis showed a 40% reduction in the need for additional fetal blood sampling (FBS) when using STAN in comparison to conventional CTG. The second part of this thesis therefore elaborates on the STAN guidelines and on its recommendations for additional fetal blood sampling. We showed that FBS performed according to these criteria revealed acidosis (defined as pH