Cystoscopic placement of transurethral stent in a fetus with urethral stenosis.

We report the case of a fetus with severe megabladder, displaying the 'keyhole' sign on ultrasound imaging, that underwent cystoscopy at 22 weeks' gestation. There was a familial history of mild urethral atresia. Fetal cystoscopy revealed congenital urethral atresia. A guide wire was advanced through the fetal urethra and a transurethral vesicoamniotic stent was placed successfully. The fetus was delivered at 36 weeks' gestation and postnatal cystoscopy confirmed the absence of posterior urethral valves or urethral atresia. The infant was 5 years old with normal renal function at the time of writing. We conclude that fetal cystoscopic placement of a transurethral stent for congenital urethral stenosis is feasible.

Fetal nasal bone length: reference range and clinical application in ultrasound screening for trisomy 21.

OBJECTIVES: Fetuses with trisomy 21 typically present with subtle facial abnormalities, including a hypoplastic nasal bone. The aim of this study was to provide a reference range for the length of the fetal nasal bone and to test its value in second-trimester ultrasound screening for trisomy 21. DESIGN: A reference range of fetal nasal bone length was established from cross-sectional data on 1923 consecutive singleton pregnancies scanned at 16-24 weeks' gestation in women older than 35 years. Screening for trisomy 21 was prospectively studied using the measurement of fetal nasal bone lengths smaller than the 5(th) percentile as a cut-off value. RESULTS: Follow-up was possible in 1631 cases (84.8%). Trisomy 21 was found in 22 cases (1.35%). Nasal bone length measurement increased as a function of gestational age (P < 0.05) showing a linear relationship. Screening for trisomy 21 using the 5(th) percentile as a cut-off value resulted in a sensitivity of 59.1% for a 5.1% false-positive rate. The likelihood ratio was 11.6. CONCLUSION: Screening for trisomy 21 using fetal nasal bone length measurements showed a sensitivity comparable to that of maternal biochemistry for a given false-positive rate of 5%. Association of nasal bone lengths with other sonographic markers, taking into account the background risk for maternal and gestational age, may further improve sensitivity and reduce false positives, allowing avoidance of unnecessary invasive diagnostic procedures.