FETAL BILATERAL OBSTRUCTIVE UROPATHY - A SERIES OF 9 CASES

Bilateral obstructive uropathy is increasingly diagnosed in early preg nancy by ultrasound examination. Termination of pregnancy presented an opportunity to study uropathy in nine cases between 18 and 24 weeks o f gestation. En bloc dissection of the urinary tract and subserial sec tioning of the urethra revealed obstruction at the level of the membra nous urethra in all cases. No structural obstruction could be demonstr ated in three cases, and urethral valves caused partial obstruction in two cases. The urethra was distorted by a fibrous band in one case. I n three cases overriding urethral lumens appeared to represent incompl ete or faulty canalization at the angled junction of the developing po sterior and anterior urethra. Urethral obstruction is considered the m ajor etiologic factor in the development of bilateral fetal uropathy a nd presumably the prune-belly phenotype.