[Vaginal sonographic assessment of a cross section of the amniotic sac in early pregnancy].

The present study describes the results of gestation sac measurement in 237 cases in early pregnant women by the technique of transvaginal sonography. Mean distance between uterine cavity and vaginal scanner probe is the reason for early detection of the gestation ring. Comparing with the transabdominal method the gestation sac can be ascertained one week earlier when performing transvaginal sonography, so that a detection of an intrauterine ring-shaped structure is possible to a time when in case of an unknown pregnancy regular menstrual bleeding is expected. Up the 10th week of gestation the amnion sac diameters are constantly smaller than the diameter obtained by transabdominal sonography, from the 11th week on results in both techniques are approximately equal. The early measurement of gestation sac diameter is usefull to determine correct gestation age in case of unknown conception date. From our point of view the gestation ring diameters, obtained by transabdominal technique should not be used father more for pregnancy determination when choosing the transvaginal method.