Ecografía Doppler en la gestación normal: circulación umbilical

Material and methods: One hundred and sixteen pregnant women carrying a single fetus have been studied. These women had no risk factors, with both clinical and analytical controls, as well as ultrasound scans, all being normal. There were performed a total of 193 Doppler ultrasound scans between weeks 15 and 41 of gestation, with bloodflow analysis in the arteries and vein of the umbilical cord. The obtained information was correlated with parameters that evaluate fetal well-being (fetal monitoring and/or oxitocin test) and perinatal result (delivery type, bithweight, Apgar score). Statistical analysis was performed with the programs SPSS 6.0.1. for Windows and EPIINFO 6.0.4.. Results: With pulsed Doppler, the umbilical artery in all cases demonstrated a biphasic morphology with systolic and dyastolic components and without retrograde blood flow. As the gestation period increased, there was observed a progressive decrease in resistance along with an increase in blood-flow velocity during the dyastolic phase. Conclusions: The Doppler ultrasound scan is a non-invasive method that permits the hemodynamic study of umbilical blood circulation. A knowledge of normal blood-flow signal morphology, as well as of the normal values for Doppler indices in relation to gestational age would permit us to utilize this method in high-risk pregnancies.