The increase of renal pelvis dilatation in the fetus and its significance

Objective To determine the effects of the changes in fetal renal pelvis dil atation on post-natal diagnosis and outcome. Methods Prenatal sonographic fetal renal anteroposterior diameters of great er than or equal to4 mm in the second trimester, which persisted to greater than or equal to7 mm in the third trimester, were the inclusion criteria. Fifty-six fetuses and 73 renal units with normal karotypes and a solitary s onographic finding of renal pyelectasis, which met the inclusion criteria, were followed, post-natally, until the age of 30 months. The neonates were categorized into three groups, according to their final diagnosis: No hydro nephrosis, pelvi-ureteric junction obstruction and hydronephrosis from othe r causes. The neonates were also categorized according to their outcome: no treatment, follow-up only and surgical treatment. Results In 17 neonates (30.4%), and 19 renal units, the diagnosis of hydron ephrosis was excluded post-natally. In 39 neonates (69.6%), and 54 renal un its, an urinary tract pathology was confirmed. The dynamics of pyelectasis in the second and third trimesters of pregnancy differed significantly amon g the neonates when categorized according to the final diagnosis (P < 0.05) , or according to outcome (P < 0.05). Conclusion: It is possible to predict, and distinguish between, long-term c onservative and surgical treatments of renal pelvis dilatation in the third trimester of pregnancy.