[Development of utero-chorionic vascular resistance in early pregnancy]

The physiologic evolution of the utero-chorionic vascular resistances during the first trimester of pregnancy is described. With the use of pulsed Doppler, 25 normal pregnancies were followed weekly, performing 288 scans between the 6th and the 12th weeks of pregnancy. The detection of the FVW was done at the level of the uterine and retro-chorionic vessels. There is a progressive decrease of the vascular resistances to flow, with significant differences (p less than 0.001) between the values before and after the 9th week. The physiologic implications and its possible application to the study of the gestational pathology are commented.