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.


STUDY DESIGN
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.


CONCLUSION
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.
['Weyrich|Joy|J|', 'Setter|Anna|A|', 'Müller|Alexander|A|', 'Schmidt|Georg|G|', 'Brambs|Christine E|CE|', 'Ortiz|Javier U|JU|', 'Lobmaier|Silvia M|SM|']
D000328:Adult D001623:Betamethasone D005260:Female D005323:Fetal Monitoring D005325:Fetal Organ Maturity D005865:Gestational Age D005938:Glucocorticoids D006340:Heart Rate, Fetal D006801:Humans D007273:Injections, Intramuscular D008137:Longitudinal Studies D008168:Lung D011247:Pregnancy D011256:Pregnancy Outcome D011446:Prospective Studies D013997:Time Factors
Betamethasone Phase-rectified signal averaging Antenatal corticosteroid Average acceleration capacity Average deceleration capacity Fetal heart rate variability