Umbilical artery blood velocimetry: a prospective longitudinal study in search of the intrauterine growth-retarded fetus

Abstract

In a longitudinal prospective study involving 125 patients, blood velocity waveforms in the umbilical artery were recorded and analyzed from the 15th week of gestation until term to evaluate the predictive value of blood velocity parameters with regard to fetal growth retardation. Measurements were performed with a combined real-time linear array and 2-MHz pulsed Doppler technique. The mean values ( ± 2 S.D.) of the A/B ratio, resistance index (RI) and pulsatility index (PI) were calculated from the 15th to the 40th week of gestation. The degree of intrauterine growth retardation was related to postnatal catch-up growth. Three groups of patients were compared with regard to blood velocity waveform indices. Group NLI/II: waveform indices (WI) within 2 S.D. of the population mean. Group EL-I: at least a single WI above 2 S.D. of the population mean. Group EL-II: consistently WIs above 2 S.D. of the population mean. Significant differences with regard to neonatal growth variables were found between these groups. In spite of the fact that these differences in growth variables were statistically significant, no clear relationship was found between the velocity waveform indices and true intrauterine growth retardation, defined by a non-birthweight criterion. It seems that umbilical artery velocimetry cannot predict true intrauterine growth retardation.