ABSTRACT
An abnormality involving the genitourinary tract is detected in 1 in 50 to 1 in 100 pregnancies, depending on the sonographic criteria. The goal of management is to recognize and treat congenital anomalies that may adversely affect renal function or cause urinary tract infection (UTI) or sepsis. The kidney is derived from the ureteral bud and the metanephric blastema. During the fifth week of gestation, the ureteral bud arises from the mesonephric duct and penetrates the metanephric blastema, which is an area of undifferentiated mesenchyme on the nephrogenic ridge. When a fetus is identified with a suspected urinary tract abnormality, the goals of management include determining the differential diagnosis, assessing the associated anomalies, and determining the fetal and postnatal risk of the anomaly. At birth, the abdomen is inspected to detect the presence of a mass, which most often is secondary to a multicystic dysplastic kidney or ureteropelvic junction (UPJ) obstruction.
