The influence of betamethasone on fetal heart rate variability, obtained by non-invasive fetal electrocardiogram recordings

Abstract

BackgroundBetamethasone is widely used to enhance fetal lung maturation in case of threatened preterm labour. Fetal heart rate variability is one of the most important parameters to assess in fetal monitoring, since it is a reliable indicator for fetal distress. AimTo describe the effect of betamethasone on fetal heart rate variability, by applying spectral analysis on non-invasive fetal electrocardiogram recordings. Study designProspective cohort study. SubjectsPatients that require betamethasone, with a gestational age from 24 weeks onwards. Outcome measuresFetal heart rate variability parameters on day 1, 2, and 3 after betamethasone administration are compared to a reference measurement. ResultsFollowing 68 inclusions, 12 patients remained with complete series of measurements and sufficient data quality. During day 1, an increase in absolute fetal heart rate variability values was seen. During day 2, a decrease in these values was seen. All trends indicate to return to pre-medication values on day 3. Normalised high- and low-frequency power show little changes during the study period. ConclusionsThe changes in fetal heart rate variability following betamethasone administration show the same pattern when calculated by spectral analysis of the fetal electrocardiogram, as when calculated by cardiotocography. Since normalised spectral values show little changes, the influence of autonomic modulation seems minor.