Heart-rate variation and movement incidence in growth-retarded fetuses with decelerative heart rate patterns. Correlations with fetal acid-base status

Abstract

Publisher Summary This chapter discusses when heart rate variation and movements decrease in intrauterine growth-retarded fetuses (IUGR) fetuses. It also discusses their relationship to the acid–base status at delivery. The chapter presents the first results obtained from 18 IUGR fetuses from whom combined recordings of fetal heart rate (FHR) and fetal motility were obtained shortly before Caesarean section. Although the IUGR group consisted of highly compromised fetuses, according to the antenatal FHR tracings, only one of the liveborn infants had a pHua lower than 7.15. This finding confirms earlier studies showing that only terminal heart rate records are associated with fetal acidemia. Hypoxia, on the other hand, may play a role as umbilical arterial PO 2 values were significantly lower than in the control group. From experimental studies in growth retarded fetal sheep, it is known that low arterial PO 2 values precede acidemia. A further indication for the role of hypoxia is the fact that the reduction of heart rate variation apparently coincides with the occurrence of late decelerations, the latter being thought to indicate hypoxemia. As for the body movement incidence, there is a weak relationship with the umbilical artery pH and this might become more evident if more fetuses in a terminal condition can be included in the study group. Further research is required to ascertain the particular effects of low PO 2 values or preferably of accurately measured oxygen saturation.