The study groups comprised 61 pregnant women whose gestational age ranged from 7 to 12 weeks from the last menstrual period. All patients apparently had a normal developing pregnancy; there were no clinical symptoms of pathology e.g. bleeding in early pregnancy. Eighty-two patients with a clinically and ultrasonographically normal pregnancy whose gestational age ranged from 7 to 12 weeks, served as a control group. When the anatomical position of investigated area have been obtained clearly, pulsed wave Doppler sample volume was placed on the structures of interest: the both uterine arteries and intervillous space. There is no statistically significant difference between the Resistance Index (RI) in the left or right uterine artery (P > 0.01) and among investigated groups of patients (P > 0.01). The intervillous blood flow RI in the case of molar pregnancy was 0.38 with SD +/- 0.03; in blighted ovum 0.43 with SD +/- 0.03, and in missed abortion 0.43 with SD +/- 0.02. It should be stressed that in nine (31%) cases of blighted ova and in five (26%) cases of missed abortion, intervillous space flow could not be detected. In the control group, intervillous blood flow was always visualized and the mean RI was 0.45 with SD - 0.04. Statistical analysis showed significantly higher RI in control group in comparison with other groups of patients (P < 0.01), and significantly lower RI in molar pregnancy in comparison with other groups of patients (P < 0.01). There was no difference in RI between blighted ova and missed abortions (P > 0.01).