The role of transvaginal sonography in chorionic villi sampling

Vaginosonography has the potential of improving not only accurate diagnosis preceeding chorionic villus sampling but also the sampling procedure itself. The vaginosonographic diagnostic landmarks of early pregnancies are the contact area between the amnion and the chorion, the insertion of the umbilical cord, the yolk sac and the decidua-trophoblast complex. The occurrence of a "Swiss-cheese-pattern" in the latter structure is a strong hint for an unfavourable outcome of early pregnancy. Vaginosonographically guided puncture is a promising approach for chorionic villus biopsy. The punturing facilities are firmly attached to the high resolution vaginal ultrasound probe. Thus, precise ultrasound-guided puncture penetrating the vaginal skin and the uterine wall in the shortest possible distance has become possible.