Change in heart rate variability in relation to a significant ST-event associates with newborn metabolic acidosis.
OBJECTIVE
To find whether low-to-high frequency (LF/HF) ratio of fetal heart rate (FHR) variability changes in relation to a significant ST-event during delivery, and if the change is predictive of metabolic acidosis of the newborn.


METHODS
A case-control study.


METHODS
Data from a multicentre project.


METHODS
Acidotic and control fetuses with abnormal cardiotocography together with a ST-event in fetal electrocardiogram (ECG).


METHODS
We studied intrapartum FHR variability with spectral analysis from 34 fetuses with a significant ST-event in the fetal ECG. LF/HF ratio of FHR variability was measured within a period of 1 hour before and 1 hour after a significant ST-event. Sensitivity and specificity of the change in LF/HF ratio of FHR variability in prediction of metabolic acidosis (pH < or = 7.05 and base deficit value > 12.0 mmol/l) of the newborn were described by means of the receiver operating characteristic curve.


METHODS
Change in LF/HF ratio of FHR in relation to a significant ST-event.


RESULTS
We found that a relative change in LF/HF ratio greater than 30% in relation to a significant ST-event predicted cord arterial metabolic acidosis with a sensitivity of 89% (95% CI 68-100%) and specificity of 80% (95% CI 64-96%).


CONCLUSIONS
Relative changes in LF/HF ratio of FHR variability in relation to a significant ST-event are more pronounced in fetuses born with metabolic acidosis.
Siira
S
S
Research Centre of Applied and Preventive Cardiovascular Medicine, University of Turku, Turku, Finland. saila.siira@fimnet.fi
Ojala
T
T
Ekholm
E
E
Vahlberg
T
T
Blad
S
S
Rosén
K G
KG
D000138:Acidosis / Q000175:diagnosis* / Q000503:physiopathology; D001145:Arrhythmias, Cardiac / Q000175:diagnosis* / Q000503:physiopathology; D015148:Cardiotocography; D016022:Case-Control Studies; D004562:Electrocardiography; D005315:Fetal Diseases / Q000175:diagnosis* / Q000503:physiopathology; D005865:Gestational Age; D006340:Heart Rate, Fetal / Q000502:physiology*; D006801:Humans; D007231:Infant, Newborn