The process of implantation plays an important role during the subsequent evolution of pregnancy. In this process, the trophoblasts have a key role by invading the spiral arteries of the miometrium, thus causing a decrease in vascular resistance in uterine arteries.The goal of this study is to investigate the utero-placental circulation in order to develop screening methods for early diagnosis of high-risk pregnancies.We followed up pregnancies in the first trimester. Biometry and utero-placental circulation was studied with ultrasound. Statistical analysis was performed with Student’s t-Test. With the progress of pregnancy we found that the impedance to flow shows a significant decrease. We couldn’t find significant differences between the impedance to flow of the right and left uterine arteries if the placental site was right or left. We couldn’t find significant differences between the impedance to flow of the uterine arteries if the placental site was anterior, posterior or fundical.
Keywords: first trimester, Doppler ultrasound, placenta