Gravidic hypertension remains one of the most frequent causes of perinatal mortality and morbidity. There are two aims when investigating this disease: evaluate the gravity, try to find early signs of a risk of pre-eclampsia. This last point has become particularly important over the past few years because of the development of preventive treatment (platelet anti-agregates). Mother and fetal blood velocimetry play a more and more important role. Three measurement sites appear to have different and complementary importance: for long-term prediction, measuring the velocimetric index of the uterin artery seems the most interesting because it schematically explores the type of placentations; for mid-term, measuring the ombilical artery evaluates placenta resistance, an essential factor in chronic fetal suffering; at short-term, measuring the fetal cerebral and carotid vessels explores the hemodynamic reactions of fetal adaptation to fetal suffering.