DEPENDENCE OF AORTIC PULSE-WAVE ASSESSMENTS ON BEHAVIORAL STATE IN NORMAL TERM FETUS

To investigate any influence of behavioural states on the pulse waves in the descending aorta, 21 human fetuses were studied in utero in unc omplicated gestation at the age of 36-41 weeks. The fetal behavioural stales were identified using two real-time scanners and one cardiotoco graph. The aortic waveform data and pulse wave velocity (PWV) were rec orded by means of two double phase-locking echo-trackers. The PWV of t he fetal aorta was significantly lower in fetal behavioural state (FBS ) 2F than in FBS 1F, when the fetus was apnoeic, and was also reduced in both states during fetal breathing. The calculated pulse pressure s howed the same trend as the PWV. The fetal aortic ehd diastolic diamet er and the pulse amplitude did not alter, when the two states changed. Our data suggest that the central haemodynamics in term fetuses are i ndependently influenced by their behavioural state as well as by fetal breathing. The study of pulse waves in the fetal aorta should prefera bly be performed during apnoea in state 1F, when neither gross body mo vements nor breathing movements disturb the recording. (C) 1997 Elsevi er Science Ireland Ltd.