Longitudinal progression of fetal short-term variation and average acceleration and deceleration capacity after antenatal maternal betamethasone application.
OBJECTIVE
To analyze the effect of maternal betamethasone given for fetal lung maturation on fetal short-term variation (STV) and average acceleration and deceleration capacity (AAC/ADC). Both of these factors are calculated by phase-rectified signal averaging (PRSA) and represent new parameters to assess the fetal autonomic nervous system.


METHODS
A longitudinal prospective study including 26 pregnant women at risk for preterm delivery was performed. Two injections of 12mg betamethasone were administered intramuscularly at a 24h interval for lung maturation. Cardiotocography recordings were performed at defined time intervals: day 0 (before the first injection) and days 1, 2, 4 after the first corticosteroid administration. AAC/ADC and STV were calculated.


RESULTS
An increase of all parameters (STV, AAC and ADC) was documented between day 0 and day 1. Between day 1 and day 2, all three indices were significantly reduced (p<0.05). STV declined by 19.8%, AAC by 10.1% and ADC by 14.8%. A normalization of these values was seen after 96h.


CONCLUSIONS
Similar to STV, AAC/ADC shows significant changes after maternal betamethasone administration. The corticosteroid-induced transient decrease of the levels needs to be taken into account in the assessment of the fetal status to avoid misinterpretation of these parameters.
Frauenklinik und Poliklinik, Technische Universität München, Munich, Germany. Electronic address: joy.weyrich@tum.de.
Joy
J
Weyrich
Frauenklinik und Poliklinik, Technische Universität München, Munich, Germany; Department of Neurology, Klinikum Leverkusen, Leverkusen, Germany.
Anna
A
Setter
I. Medizinische Klinik, Technische Universität München, Munich, Germany.
Alexander
A
Müller
I. Medizinische Klinik, Technische Universität München, Munich, Germany.
Georg
G
Schmidt
Frauenklinik und Poliklinik, Technische Universität München, Munich, Germany.
Christine E
CE
Brambs
Frauenklinik und Poliklinik, Technische Universität München, Munich, Germany.
Javier U
JU
Ortiz
Frauenklinik und Poliklinik, Technische Universität München, Munich, Germany.
Silvia M
SM
Lobmaier
D000328:Adult; D001623:Betamethasone / Q000008:administration & dosage / Q000493:pharmacokinetics*; D005260:Female; D005323:Fetal Monitoring; D005325:Fetal Organ Maturity / Q000187:drug effects; D005865:Gestational Age; D005938:Glucocorticoids / Q000008:administration & dosage / Q000494:pharmacology*; D006340:Heart Rate, Fetal / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D007273:Injections, Intramuscular; D008137:Longitudinal Studies; D008168:Lung / Q000187:drug effects / Q000196:embryology; D011247:Pregnancy; D011256:Pregnancy Outcome; D011446:Prospective Studies; D013997:Time Factors
D005938:Glucocorticoids; D001623:Betamethasone
Antenatal corticosteroid; Average acceleration capacity; Average deceleration capacity; Betamethasone; Fetal heart rate variability; Phase-rectified signal averaging