Objective: To establish a cut-off value for short-term variation (STV) assessed by computerized cardiotocography (CTG) as a single parameter in the prediction of acidemia at birth.
Methods: Cross-sectional study performed on 41 single gestations with diagnosis of hypertension syndrome after the 27th week and delivered by elective cesarean. Computerized CTG examinations were 20-min long at most, and were performed up to 24 before delivery. Immediately after delivery, blood samples were collected from the umbilical cord vessels to determine pH. To establish a cut-off value, a receiver operator characteristics (ROC) curve was created with STV as independent variable and umbilical artery pH as dependent variable. Later, sensitivity (S), specificity (E), positive predictive value (PPV), and negative predictive value (NPV) were calculated for the cut-off value obtained.
Results: A significant correlation was found between STV and acidemia at birth, and STV values < or =5.25 ms were significantly capable of predicting acidemia (pH < 7.20) (S = 57.1%; E = 85.2%; PPV = 66.6%; NPV = 79.3%; P < 0.05).
Conclusions: STV values of < or =5.25 ms could predict acidemia at birth in pregnant women with hypertension syndrome.