Fetal bladder morphology as a predictor of outcome in fetal lower urinary tract obstruction.

Objective: We evaluate survival of fetuses with severe Lower Urinary Tract Obstruction (LUTO) based on bladder morphology. We hypothesize that fetuses with a "floppy" appearing bladder on initial prenatal ultrasound will have worse infant outcomes than fetuses with full/rounded bladders. Method: We retrospectively reviewed all cases of LUTO evaluated in our fetal center between January 2013 and December 2021. Ultrasonographic assessment, renal biochemistry, and bladder refilling contributed to a "favorable" or "unfavorable" evaluation. Bladder morphology on initial ultrasound was classified as "floppy" or "full/rounded." Vesicoamniotic shunting was offered for favorably evaluated fetuses. Baseline demographics, ultrasound parameters, prenatal evaluations of fetal renal function, and infant outcomes were collected. Fetuses diagnosed with severe LUTO were included in analysis using descriptive statistics. The primary outcome measured was survival at 6 months of life. Results: 104 LUTO patients were evaluated; 24 were included in analysis. Infant survival rate at 6 months was 60% for rounded bladders and 0% for floppy bladders (p = 0.003). Bladder refill adequacy was lower in fetuses with floppy bladders compared with rounded bladders (p value < 0.00001). Conclusion: We propose that bladder morphology in fetuses with severe LUTO may be a prognostication factor for predicting infant outcomes and provides a valuable, noninvasive assessment tool. Key points: What is already known about this topic?Fetal urinary biochemistry and ultrasound have been useful in predicting when fetal intervention may be beneficial in cases of Lower Urinary Tract Obstruction (LUTO), but it remains difficult to determine prognosis prenatally and neither method has been found to be independently reliable. What does this study add?We propose that the addition of bladder morphology to the current LUTO evaluation methods provides a noninvasive method to prognosticate outcomes and determine candidacy for fetal intervention. [ABSTRACT FROM AUTHOR]