ISOLATED FETAL PYELECTASIS - ASSESSMENT OF RISK FOR POSTNATAL UROPATHY AND DOWN-SYNDROME

Eighty-two consecutive fetuses with ultrasound evidence of isolated py electasis (defined as dilation in the antero-posterior renal pelvic di mension of greater than or equal to 4 mm) were prospectively followed to determine the risk for postnatal uropathy and Down syndrome. In 98 (60%) kidneys, isolated pyelectasis was shown to be the first manifest ation of a pathophysiological process that evolved into a gamut of pos tnatal uropathies (defined as urological conditions requiring remedial surgery of extended medical surveillance). Data quantifying the risk for postnatal uropathy in fetuses with varying degrees of isolated pye lectasis, at different gestational ages, are presented in figure forma t to facilitate prenatal counselling. Bivariate analysis showed that t he evolution of isolated pyelectasis to uropathy was statistically sig nificant when in utero progression was noted or in conjunction with ot her findings including contralateral pyelectasis (p < 0.01), male gend er (p < 0.01) and increased kidney length (p < 0.002). Importantly, 55 % of the infants requiring corrective surgery demonstrated in utero pr ogression of pyelectasis (p < 0.002). Serial ultrasound examinations w ere necessary to evaluate progression or regression in the extent of p yelectasis. Finally isolated pyelectasis was associated with an increa sed risk for Down syndrome, beginning at maternal age of 31 years, in the internal of 16-20 weeks' gestation.