Predictive factors of fetal urethral obstruction: a multivariate analysis

Abstract

Objective: The purpose of this study was to identify predictive factors of fetal urethral obstruction.

Methods: One hundred and forty-eight children with fetal hydronephrosis were admitted, submitted to a systematic protocol and prospectively followed. Possible predictive factors of urethral obstruction associated with fetal echography and clinical findings on admission were studied. The analysis was conducted in two steps. In a univariate analysis, variables associated with urethral obstruction were identified by the chi(2) test or by Fisher's exact test. Then, the variables that were significantly associated with urethral obstruction were included in a multiple logistic regression analysis.

Results: After final adjustment by multiple logistic regression analysis, only two variables were identified as independent predictors of fetal urethral obstruction: oligohydramnios (odds ratio, OR = 5, 95% confidence interval, CI, = 1.3-15, p = 0.01) and megacystis (OR = 9, 95% CI = 2.0-40, p = 0.004). The sensitivity and specificity of the combination of both variables were 60 and 98.5%, respectively.

Conclusions: The presence of oligohydramnios and megacystis on prenatal ultrasound is highly predictive of fetal urethral obstruction.