Fetal blood flow velocity waveforms as predictors of growth retardation.

Seventy-five high-risk pregnancies were studied in order to define the clinical value of the analysis of fetal blood flow velocity waveforms in early screening for growth retardation. Recordings were obtained at 26-28 weeks' gestation, in the absence of ultrasonographic signs of growth retardation, using a pulsed duplex Doppler system. The pulsatility index was evaluated at the level of the umbilical artery, descending aorta, and internal carotid artery. Fetuses (N = 23) who developed growth retardation showed higher values of pulsatility index in the umbilical artery (P less than .001) and descending aorta (P less than .05) than fetuses of normal growth. In the internal carotid artery, the pulsatility index was lower (P less than .001) in the fetuses who developed growth retardation than in those with normal growth. The ratio between the pulsatility indexes of the umbilical and internal carotid arteries proved an accurate predictor of growth retardation (specificity 92.3%; sensitivity 78.2%; positive predictive value 81.8%; negative predictive value 90.5%; accuracy 88%).