Endovaginal sonographic diagnosis of the fetal urinary tract anomalies in early pregnancy.

Transvaginal sonography has enhanced the ability to follow fetal development and detect pathologies in early gestation. Examination of the fetal urinary tract is an integral part of routine sonographic examinations in the second trimester of pregnancy and one of the major benefits of prenatal sonography is to allow early diagnosis of relatively common urinary tract malformations. Detailed evaluation of the fetal urinary tract and identification of anomalies were considered to be difficult before the 18th week of gestation prior to the use of transvaginal sonography. Using the transvaginal route, a detailed evaluation of the kidneys is possible around 12 weeks and structural anomalies of the urinary tract are being detected at an ever-increasing rate. Transvaginal sonography, owing to its proximity to the maternal pelvic organs, allows an earlier determination of the normal fetal urinary system and more accurate diagnosis and identification of fetal urinary anomalies as compared with transabdominal ultrasound.