Abrupt fall in the fetal heart rate during labour.

Cardiotocograms of 6044 patients in labour were examined for evidence of an abrupt fall in the fetal heart 50 beats within 3 minutes, without a demonstration of signs of recovery in the following 2 minutes. Only 9 instances could be found -- an incidence of 0,15%. Umbilical cord entanglement possibly played a role in 6 of these instances, and 2 of the infants concerned were stillborn. Intra-uterine growth retardation was associated with deceleration in 3 infants, 1 of whom was stillborn.