Correlation between Nonreassuring Patterns in Fetal Cardiotocography and Birth Asphyxia

Cardiotocography (CTG) is a tool for assessing the fetus during labor and identifying the risk of asphyxia. Abnormal CTG can lead to stress in the physician and mother and result in their decision in terminating the pregnancy and the complications of an emergency cesarean section. The purpose of this study was the evaluation of the correlation between nonreassuring patterns in fetal CTG and birth asphyxia. In a cross-sectional analytic study, 324 term pregnant women were included. The association between nonreassuring patterns in CTG (fetal tachycardia, fetal bradycardia, absent or minimal baseline variability, and absence of acceleration and periodic or episodic deceleration) and birth asphyxia were assessed. Birth asphyxia existed in 10 newborns; in all cases mild hypoxic ischemic encephalopathy (HIE) was observed. Within the nonreassuring CTG patterns, baseline fetal heart variability and periodic or episodic deceleration had a significant relationship with birth asphyxia. Most asphyxia cases had occurred in absent and minimal baseline fetal heart rate (FHR) variability (R = 0.49, P <. 001). In periodic or episodic decelerations, most asphyxia cases occurred in recurrent late decelerations with normal baseline variability and variable decelerations with shoulders or overshoots (R = 0.42, P =. 014). With regard to the findings of the present study we can use nonreassuring cardiotocographic patterns, especially absent and minimal baseline FHR variability and periodic or episodic decelerations in prediction of birth asphyxia. It seems however that most birth asphyxias occur in normal cardiotocographs.