[Changes in the automatically analyzed features of fetal heart rate patterns and fetal movements as influenced by atropine sulfate].

The influence of atropine sulphate (0.01 mg/kg body weight of pregnant women i.v.) on several parameters of fetal heart rate was investigated with automatic analysis of FHR. Fetal movements were counted, too. After administration of atropine, there was a first period with an "inverse" effect of atropine in all fetuses: decrease in baseline FHR (5.1%, minimum after 4.5 min) and increase in the amplitude of FHR fluctuation (44.6%). Thereafter, in a second period the "true" atropine effect appeared: increase in baseline FHR (15.5% above the level before atropine maximum after 25.1 min) and decrease in the amplitude of fluctuation (64.5%). In the third period baseline FHR returned to normal values but the amplitude of FHR fluctuation as well as the beat-to-beat irregularity remained small in 12 from 14 fetuses. Fetal movements registered by the mothers decreased significantly in this time. The results demonstrate a dualistic effect of atropine in the fetus. Moreover, the amplitude of FHR fluctuation (amplitude of macrofluctuation) and the beat-to-beat irregularity (microfluctuation) changed in an equal manner and appear to be influenced by similar regulatory processes. The divergence in the reaction of the baseline FHR and the amplitude of fluctuation together with a decrease in fetal movements might be caused by a central nervous effect with a change in the behaviour of the fetus.