[Value and significance of obstetric monitoring methods]

In a retrospective study on 224 births, 200 continuous tracings recorded during intrapartum cardiotokography were analysed for the presence of alarm signals and the incidence of fetal acidosis assessed by fetal blood sampling. Moreover, we classified the 200 monitored parturitions according to the presence of risk at the beginning and/or the appearance of alarm signals during labour into 4 groups. In 17% of the parturitions without initial risk alarm signals were subsequently recorded on CTG, whereas alarm signals occurred in 35% of high-risk births. In both groups fetal distress, as assessed by fetal blood sampling, was detected in 4%. In all investigated cases we simulated a policy of intrapartum monitoring by intermittent auscultation (IA) up to the pushing period. The CTG tracings were analysed retrospectively, whilst counting the fetal heart rate every fifteen minutes. The possible results and consequences of IA were compared with the actual results and management based on CTG alone. Vice the real management, were the decision for operative delivery after the suspected diagnosis of fetal distress had been confirmed by fetal blood sampling. The results of all three methods were compared. The superiority of CTG over IA in detecting alarming situations and fetal distress, was proven statistically. In order to prevent the unnecessary operative delivery of an infant erroneously considered to be distressed, it is mandatory to check the indication by fetal blood sampling.