Does a Nonreactive Fetal Heart Rate Pattern Really Mean Fetal Distress?

ABSTRACT

The aim of the study was to compare three different fetal heart rate (FHR) patterns, namely, a nonreactive pattern with good long-term variability (fluctuation of 5 or more beats/min), a reactive pattern, and a nonreactive pattern with poor long-term variability (less than 5 beats/min). For this purpose, nonstress tests done less than 24 hours before delivery and FHR patterns recorded during labor were separately assessed. Endpoints for comparison were 5-minute Apgar scores, intrauterine growth retardation, and umbilical blood gas values at birth. Regarding the nonstress test, the prevalence of low 5-minute Apgar scores in reactive, good variability, and in poor variability patterns were 7.2%, 5.3%, and 24%, respectively. The prevalences of small for gestational age newborns were 8%, 17.6%, and 60.6%, respectively. Blood gas values did not differ significantly. Regarding the FHR patterns during labor, using the same sequence, the prevalences of low 5-minute Apgar scores were 3.5%, 6%, and 23%, respectively. Small for gestational age babies occurred in 8.8%, 15.6%, and 80% of the different FHR patterns, respectively. Regarding umbilical artery blood gas values, the only significant difference was a lower pH in the poor variability group. No difference was found between the blood gas values of babies with a reactive pattern and a nonreactive pattern with good variability.