[Embryo-fetal ultrasonographic diagnosis in the early pregnancy using transvaginal echography]

The diagnostic capability of high resolution transvaginal sonography in early pregnancy is described. Transvaginal sonography allows for the visualisation of some fetal organs and structures one to four weeks earlier than transabdominal ultrasound thus permitting evaluation of several embryofetal parameters early in pregnancy. This technique permits formulation of fetal measurement charts and detection of embryo-fetal malformations during the initial stages of pregnancy. Knowledge of the transvaginal sonographic appearance of embryonal and fetal biometric and structural anatomy enables us to determine the appearance of the normal fetus. Transvaginal scan may be employed as a screening tool for the identification of fetal anomalies in early stages of pregnancy. An increasing number of case reports and documented records of cases of malformations and anomalies diagnosed during the first trimester of pregnancy using this technique have been reported in the literature. The most frequent embryo-fetal malformations and anomalies detected at transvaginal scan and the earliest gestational age of diagnosis are described. At present a limited number of anomalies can be diagnosed because only a part of the potentially recognizable anomalies have been described using this technique. The importance of this new imaging technique as well as the necessity of a through knowledge of embryology are evident. Transvaginal sonography allows for biometric evaluation, for a clearer visualization of embryo-fetal morphology and for detection of several malformations and anomalies during early pregnancy.