Obstruction of the lower parts of the urinary system of the fetus in the womb is observed with a probability approximately equal to one case per 5,000-10,000 infants. This disease, which is more common in male infants, manifests itself as urethral atresia, urethral obstruction, or most often as a posterior urethral valve (PUV).
The inability to properly excrete urine causes a lack of amniotic fluid, which causes abnormalities in the development of the baby’s lungs, which causes most babies to die due to lung failure immediately after birth, even if they managed to survive in the womb. A significant number of infants experience distress or death due to compression by the umbilical cord in the womb. The probability of death in the absence of treatment in such cases is approximately 90%.
The accumulation of urine in the upper section of the urinary system due to abnormalities in urination negatively affects the development of the kidneys. Therefore, even infants who survive in the absence of intrauterine treatment will require dialysis or kidney transplantation in later life.
Ensuring the proper flow of fetal urine in the womb (for example, using vesicoamniotic bypass catheters) promotes proper lung development, which prevents a lack of amniotic fluid. This increases the chances of the fetus’s life by about 4-5 times (from 10 percent to almost 50).