Spatio-temporal spectral analysis of intracerebrally recorded seizure activity : T.M. Darcey, H.P. Meles and H.G. Wieser (Zürich, Switzerland)

Abstract

The objective of this study was to identify and quantify fetal and maternal heart rate (FHR, MHR) periodicities and to examine their interrelation as well as the relation of fetal cycles with the maternal REM-NREM sleep cycle. Heart rate periodicities of the same subjects after birth were correlated with the neonatal REM-NREM sleep cycle. Sixteen all-night polygraphic recordings were obtained during the last trimester of pregnancy and the 1st week of life in seven subjects. Abdominal leads were used to obtain continuous fetal heart rates. Maternal and infant sleep states were scored according to standard criteria. Minute-by-minute values for maternal, fetal, and neonatal heart rates were analyzed on a PDP-12 computer and subjected to time series analyses including auto spectral techniques and complex demodulation. Period lengths of less than 1 h, between 1 and 2 h, and even longer were present in the tracings of mother, fetus, and neonate. Predictable interaction between maternal and fetal heart rate periodicities could not be established. None of the fetal rhythms bore a consistent relationship with the maternal REM-NREM sleep cycles. Maternal sleep onset or the first sleep cycle was accompanied by an increase in fetal heart rate lasting between 10 and 20 min in six of the nine recordings. Fetal heart rate cycles between 1 and 2 hr are probably early manifestations of the neonatal REM-NREM sleep cycle. The transient rise in fetal heart rate could be an adaptive response to either the fall in blood pressure or the shift in acid-base balance upon maternal sleep onset to which the fetus habituates within a short time.