Umbilical artery Doppler waveform in pregnancies with uncomplicated intra-uterine growth retardation.

Seventy-four pregnancies with uncomplicated intra-uterine growth retardation were assessed at the time of diagnosis by Doppler ultrasound umbilical artery flow velocity waveform. The results were not disclosed to the clinicians. Only those pregnancies with a complete absence of pre-existing disease or pregnancy complications were included. Ten patients showed evidence of fetal compromise due to asphyxia either before or during labour. In all cases the umbilical artery flow velocity waveform had been abnormal, and this abnormality always preceded cardiotocogram abnormality by up to 5 weeks. Though the resistance index was significantly associated with birth weight (p less than 0.001), this relationship was clearly dependent on the compromised fetuses who tended to be very small, and the true association is probably between resistance index and compromise, with birth weight being an intervening variable.