Mr.Kimble. My personal opinion regarding Fetal  bladder outlet obstruction-prognosis of PUV has not improved as-1. probably we haven't understood the embryogenesis properly(Prof.Stephens FD suggested faulty migration of MND  is the cause of obstruction and renal dysplasia is associated). 2.PUV constitutes around 50-60 % of BOO, while others are due to urethral atresia,MMIHS, prune belly syndrome etc.,.The latter occur early and have worse prognosis.3.May be better understanding,instumentation and technology may improve the results. Regards.