[Indications for urinary drainage in neonates detected in utero]

The routine use of maternal ultrasonography has led to increasing discovery of fetal abnormalities of the urinary tract. It is well known that some of the fetal hydronephrosis improves spontaneously, and that there is non-obstructed type of hydronephrosis. However, some of the infants require the management in the neonatal periods because of the mass effect from the dilated urinary tract, urinary tract infection, or deterioration of the renal function. Herein we report on 103 cases with urinary tract abnormalities detected by the prenatal ultrasonography, and analysed the renal function in the early neonatal periods to determine the necessity of the emergency urinary drainage. 1. Renal function of the normal neonates (control) Seventy four infants without abnormalities of the urinary tract were studied on serum creatinine (SCr) and fractional excretion of sodium (FENa) during the first four weeks of life. The SCr of infants at birth to one day postnatally was almost the same with maternal SCr. In infants with a gestational age of 33-40 weeks it fell steadily and reached the value around 0.6 mg/dl at 1 week after birth. The fall of SCr was significantly slow in infants with a GA of 28-32 weeks. Similarly, the FENa was significantly higher in infants with a GA of 28-32 weeks than in infants with a GA of more than 33 weeks. Glomerulo-tubular balance was maintained as early as 1 week postnatally in the latter group. 2. Infants treated in the neonatal periods Urological management was done on 26 infants (23%) during the neonatal periods.(ABSTRACT TRUNCATED AT 250 WORDS)