THE FIRST 3 WEEKS ASSESSED BY TRANSVAGINAL COLOR DOPPLER

Transvaginal color Doppler has made possible to study ovarian and uter ine perfusion in non-pregnant and pregnant patients, thus advancing th e understanding of the early human development. RI of follicular blood flow starts decreasing prior to ovulation reaching its nadir at ovula tion. It is considered that apart from hormonal factors the angiogenes is is also involved. The mature corpus luteum shows increased blood fl ow velocity in relation to preovulatory follicle. Comparing RI values of luteal blood flow of normal and ectopic pregnancy no difference was found. But in threatened, incomplete and missed abortions the resista nce and pulsatility indices were significantly higher than in normal p regnancy. The follow up of the luteal flow might have a prognostic val ue in a group of patients with threatened abortion. In women with spon taneous cycles the day preceding the ovulation impedance to uterine fl ow velocity starts decreasing. Alterations in flow velocity patterns o f the radial and spiral arteries in spontaneous ovulatory cycles are p aralleling blood flow dynamics of the uterine arteries. In stimulated cycles RI increases the day before ovulation in both the uterine arter ies and their branches. It seems that endometrial perfusion presents m ore accurate noninvasive assay of uterine receptivity than uterine art ery perfusion alone. Endometrial receptivity is maximum during the tim e of peak luteal function during which implantation is most likely to occur. During the pregnancy impedance to blood flow decrease from the main uterine to the spiral arteries as well as with the advancing gest ational age. The spiral arteries in pregnancy become the vessels with completely different haemodynamic characteristics in relation to other arteries of uteroplacental circulation. Color Doppler adds new inform ation on perfusion and pathophysiological changes connected with the e ctopic trophoblast implantation.