Fetal heart rate patterns and ECG ST segment changes preceding metabolic acidaemia at birth.
OBJECTIVE
To compare the rates of abnormal ST segment patterns of the ECG and cardiotocographic (CTG) abnormalities in fetuses with metabolic acidaemia at birth and controls. To evaluate the inter-observer agreement in interpretation of ST analysis and CTG.


METHODS
Case-control study.


METHODS
Three University hospitals in southern Sweden.


METHODS
Cases and controls were selected from the Swedish randomised controlled trial on intrapartum monitoring, including 4966 fetuses monitored with a scalp electrode.


METHODS
Two obstetricians independently assessed the CTG and ST traces of 41 fetuses with metabolic acidaemia at birth and 101 controls, blinded to group, outcome and all clinical data. They classified each CTG trace and ST analysis as abnormal or not abnormal, and whether there was indication to intervene according to the CTG or to the CTG + ST guidelines. If their classification differed, assessment by a third obstetrician determined the final classification.


METHODS
Rates of CTG and ST abnormalities and decisions to intervene. Rates of inter-observer agreement.


RESULTS
CTG was classified as abnormal in 50% and ST in 63% of cases with acidaemia, and in 20% and 34% of controls, respectively. CTG abnormalities were judged to be indication for intervention in 45% and CTG + ST abnormalities in 56% of cases with acidaemia, and in 15% and 8% of controls, respectively. The proportion of agreement between the two initial observers was significantly higher for ST abnormalities (94%) than for CTG abnormalities (73%), and for indication to intervene according to CTG + ST (89%) than according to CTG alone (76%).


CONCLUSIONS
The inter-observer agreement rate was higher for a decision to intervene based on CTG + ST than on CTG alone.
Amer-Wåhlin
Isis
I
Department of Obstetrics and Gynaecology, University Hospital Lund, S-221 85 Lund, Sweden.
Ingemarsson
Ingemar
I
Marsal
Karel
K
Herbst
Andreas
A
D000138:Acidosis / Q000151:congenital / Q000503:physiopathology*; D001145:Arrhythmias, Cardiac / Q000151:congenital / Q000503:physiopathology*; D015148:Cardiotocography / Q000379:methods; D016022:Case-Control Studies; D004562:Electrocardiography / Q000379:methods; D004566:Electrodes; D005315:Fetal Diseases / Q000503:physiopathology*; D006340:Heart Rate, Fetal / Q000502:physiology*; D006801:Humans; D007231:Infant, Newborn; D015588:Observer Variation; D012680:Sensitivity and Specificity