Umbilical artery Doppler blood flow studies in the preterm, small for gestational age fetus.

Umbilical artery Doppler studies were performed on the day of delivery in 15 singleton preterm pregnancies. In each case the fetus was significantly growth retarded on ultrasound examination and the attending obstetrician had made a decision to deliver the patient of the infant. Eight women had severe preeclampsia, three had mild chronic hypertension, and in four there was no recognized maternal disorder. Doppler studies were analyzed by use of the pulsatility index and the A/B ratio. In 14 of the 15 cases both were markedly abnormal. Three early neonatal deaths occurred. A positive correlation was found between the degree of abnormality of the pulsatility index and A/B ratio and a poor neonatal outcome (p less than 0.001 and p less than 0.02). Umbilical artery Doppler studies were not helpful in differentiating between intrinsic and extrinsic causes of growth retardation but seemed to identify the pregnancy at increased risk of a poor neonatal outcome.