Acceleration patterns of the fetal heart rate before and during labour.

In infants in whom accelerations of the fetal heart rate were present during the first stage of labour, the incidence of low Apgar scores was significantly less than in those in whom accelerations were not present. Absence of acceleration patterns during the contraction stress test (CST) was associated with a lower birth weight. In patients in whom acceleration patterns were observed during a positive CST, fetal distress occurred in the minority of subsequent labours. When accelerations as well as late decelerations are observed during a CST, the possibility of a false positive test should be excluded.