THE FATAL ABNORMALITIES OF THE KIDNEY AND URINARY TRACT OF THE FETUS. THE PRENATAL DIAGNOSIS – THE DIFFICULT DECISION
The ultrasound identification of the variants of the congenital urinary tract abnormalities, the detection of severity of deterioration and poor renal prognosis – are the significant goals of antenatal diagnostics. The literature review on prenatal ultrasonic diagnostics of kidney and urinary tract abnormalities of the fetuses with poor prognosis is represented. The new concept of differential diagnostics of variants of abnormalities of the fetus is based on the functional principle of ultrasound monitoring of the urinary tract of the fetus, controlling the bladder volume, micturition cyclings, hourly urine production. The fetal urinary tract abnormalities with poor prognosis include obstructive urodynamic anomalies: posterior urethral valves, Prune-Belly syndrome, syndrome megacystis-megaurether-microcolon, and the group of abnormalities without urodynamic obstruction: bilateral kidney agenesis, polycystic kidney disease, extrophy. 
 The complex of the objective urodynamic criteria, confirming to define poor prognosis of the obstructive urinary tract anomalies are based on: megacystis syndrome, pathological voiding: atonic or obstructive, residual urine ≥ 80%, sharp depression of a diuresis. The urodynamic criteria of the group of fetal abnormalities without urinary tract obstruction are based on microcystis syndrom or absence of visualization of the bladder, depression of diuresis.
 Prentenatal detection of urodynamic preconditions of life-threatening fetal urinary tract abnormalities provides the possibility for terminating the pregnancy, fetal intervention or treatment starting soon after birth and prompt intervention of the infants before sepsis and metabolic complications occurred.