P14.82: Does the obstructive level make differences in their outcomes? A study for pregnancies with fetal GI tract obstruction

Abstract

Objective: To examine the underlying pathology in male fetuses with sonographic evidence of severe and isolated LUTO. Methods: Detailed postmortem examination was carried out after termination of pregnancy in 24 male fetuses presenting before 25 weeks of gestation with ultrasound evidence of isolated severe low urinary tract obstruction. Results: Gender was male in all cases. There was megacystis and hyperechogenic kidneys in all cases. There was anhydramnios/oligohydramnios and pelvicalyceal dilatation in 20 and 15 cases respectively. Prenatal diagnosis of the underlying condition was erroneous in 2/3 of the cases. Urethral atresia was never suspected antenatally. Examination of the urethra demonstrated atresia in 6 cases, severe stenosis in 8 cases, posterior urethral valves in 9 cases and an apparently normal urethra in one. Renal dysplasia was found in all cases but one. Urethral atresia was the most common urethral anomaly at 12–17 weeks. Hydronephrosis was more frequent in cases with PUV (8/9) and urethral stenosis (6/8) than with urethral atresia (1/6). In LUTO presenting before 25 weeks hyperechogenic kidneys was predictive of renal dysplasia in 95% of the cases. The association of a bladder larger diameter of more than 40 mm and hydronephrosis in a male fetus before 25 weeks was predictive of PUV with a PPV and NPV of 44% and 100% respectively. Absence of hydronephrosis and a bladder larger diameter of less (or equal) than 40 mm were predictive of urethral atresia or stenosis with a PPV and NPV of 83% and 57% respectively. Conclusion: LUTO presenting with megacystis in a male fetus in the first and second trimester can correspond to urethral atresia or stenosis more often than posterior urethral valves. Since the formers carry a poor prognosis size of the bladder and the presence of hydronephrosis could be the most discriminant association to improve prenatal counselling.