[The influence of observer-dependent properties upon the evaluation of fetal heart rate recordings (author's transl)].

The significance of the observer's experience in the evaluation of fetal heart rate (FHR) recordings has not yet been dealt with in the literature. Therefore the qualitative and quantitative determination of these subjective factors has been studied as follows at the University of Basle Department of Obstetrics and Gynecology: Twenty FHR recordings were simultaneously analyzed by twenty-five residents with different levels of obstetrical experience. The results were compared with those of physicians with expertise in FHR monitoring. It became obvious that ominous antepartum FHR tracings were significantly less often correctly identified than harmful intrapartum recordings (p less than 0.001). Harmless changes in intrapartum FHR tracings were more frequently misjudged as being ominous than normal antepartum FHR tracings (p less than 0.05). The following conclusions were made: - There is a real danger of a fatal error in the interpretation of ominous antepartum FHR recordings. - The presented data seem to reveal the source of the increased caesarean section rate described by others as to be associated with FHR monitoring. - The errors in the interpretation of FHR tracings decrease significantly (p less than 0.05) with increasing experience. Thus physicians' education is eminently important for the correct use of electronic fetal monitoring.