More perinatal deaths associated with poor long-term variability during antenatal fetal heart-rate monitoring

Positive stress and non-stress tests of 243 infants were examined for accelerations and the duration of poor long-term variability during fetal heart rate monitoring. Accelerations were present in 47% when the variability was good. No accelerations were seen when poor variability lasted for more than 75% of the monitoring time; this was also associated with lower birth-weights, shorter gestational duration and lower 5-minute Apgar scores. These measurements improved as the period of poor variability decreased. Intra-uterine death occurred in 1.9% of infants when the variability was good, in 3.6% when the variability lasted for less than 75% of the recording time and in 19.6% when the poor variability lasted longer than 75% of the recording time. Neonatal deaths occurred in 7.5%, 11.5% and 21.7% of these three groups, respectively. Poor long-term variability was also associated with growth-retardation.