The devastation caused by fetal obstructive uropathy is now well known. At the most severe end of the spectrum of obstructive uropathy not only is the developing kidney damaged but the resultant oligohydra-mnios prevents pulmonary development and causes skeletal defects. The most significant changes are noted in patients with posterior urethral values (PUV). The obvious solution to the problem is to either correct or by pass the obstruction prior to the development of permanent changes. Unfortunately, this simple concept is not easy to apply since it raises numerous ethical, legal, economic and technical problems.