Phase-rectified Signal Averaging for the Quantification of the Influence of Prenatal Anxiety on Heart Rate Variability of Babies

The autonomic nervous system (ANS) modulates heartbeat intervals responding to inputs from its different branches, resulting in periodicities that occur on different time scales. Internal and external perturbations are continuously interrupting the periodic behavior, making the heartbeat intervals quasi-periodic. Phase-rectified signal averaging (PRSA) is a technique to detect those quasi-periodicities in noisy, non-stationary signals, like tachograms. The method compresses the tachogram in shorter curves based on internal information, and provides information on the deceleration and acceleration capacity of the heart. In this study, the PRSA technique is investigated as a novel signal processing technique for the analysis of heart rate variability (HRV) of babies. In this way, the effect of stress and anxiety during pregnancy on the ANS of the baby is analyzed. First, the PRSA curves are obtained for each baby and different measures that characterize these curves are defined. Next, these measures are linked to the anxiety level of their mothers during pregnancy. Only little influence of the anxiety level of the mother on the HRV of the baby is found.