[Influence of umbilical cord entanglement on fetal heart rate].

Umbilical cord entanglement was found in 34% of 555 women in labour. One loop of cord around the neck of the fetus was seen in 29% of the women and two or more loops in 5%. Cardiotocograms of these patients were examined for abnormal heart rate patterns. Cord involvement did not influence the incidence of basal bradycardia or tachycardia, early or late decelerations, loss of beat-to-beat variation or acceleration patterns. Variable decelerations, however, were seen in 23% of the patients with cord entanglement and in 7% without cord involvement. This difference is statistically significant (P less than 0.001). Subclassification of variable deceleration into different grades according to the amplitude of the deceleration, demonstrated the presence of cord involvement in 50% of the patients with moderate variable decelerations. This incidence rose to 65% when severe variable decelerations were demonstrated and to 75% when decelerations had increased during labour. Low Apgar scores at 1 and 5 minutes occurred 2 and 3 times more often, respectively, when cord involvement was present.