Most common anomaly of upper urogenital tract is

The most common obstructed lateral fusion defects is unilateral obstruction and is most commonly seen in women with complete duplication of the reproductive tract(double uterus, cervix and vagina) . Unilateral UPJ obstruction is the most common prenatally detected obstructive disease, often picked up on maternal ultrasounds during pregnancy. Reference: GHAI Essential pediatrics, 8th edition