Fetal autonomic nervous system activity monitoring by spectral analysis of heart rate variations

Using an accurate beat-to-beat detection algorithm for fetal heart rate (FHR) from abdominal electrocardiograms (ECGs) and spectral analysis of heart rate fluctuations, with simultaneous recording of fetal breathing movements (FBMs) by ultrasound imaging, the authors were able to display the continuous activity of the fetal autonomic nervous system (ANS). The continuous display of fetal ANS activity presented may offer an adequate tool for the evaluation of fetal viability. FHR and FBM can be measured by a single procedure. The method provides FHR and FBM as estimated by the power of HR fluctuations reflecting ANS activity in the frequency band related to FBM. Thus, two complementary indications of the fetal viability are obtained simultaneously, from a single noninvasive measurement which allows continuous time dependent monitoring