Aims: Routinely antepartal CTG will be recorded for 30 minutes to obtain normal resting phases, a decrease of irregulatory due to hypoxia or to differentiate these from each other. In case of early onset of hypoxia first pathological findings might only be seen by chance in incidentally recorded CTG. The goal of this study was, if a continuous 24 hour-CTG will allow an earlier detection of beginning hypoxia in case of placental insufficiency compared to a routine CTG of 30 minutes.
Methods: 21 normal pregnancies and 17 patients with placental insufficiency of ≥ 36 weeks had 24 hour-CTG's by means of telemetry. In both study groups fetal heart rate (FHR) tracing included a full qualitative and quantitative description. Comparison of the results of both groups was done to look for early signs of pathological findings concerning reduced fetal well-being.
Results: In comparison to normal pregnancies patients with placental insufficiency had in 4.5% oscillation frequency type A and an increase of saltatory and silent oscillation. The number of accelerations and Dip 0 was significantly reduced as well as accelerations in combination with undulatory oscillation. Baseline tachycardia and bradycardia showed significantly increasing quantity.
Conclusions: 24 hour-CTG is a good screening method to detect early onset of hypoxia in case of beginning placental insufficiency. The failure to find any clinically significant difference in the diurnal variation of both groups suggests, that less than 24 hour testing is required. 8 hour-CTG could be a compromise and a big help to detect a fetus at risk earlier.
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