Serial Amnioinfusions for Severe Fetal Urinary Conditions

Congenital lower urinary tract obstruction (LUTO) is a heterogeneous group of congenital anomalies that lead bladder outlet obstruction. If a complete obstruction is present, the perinatal mortality is estimated to be as high as 90% because of severe pulmonary hypoplasia due to the lack of amniotic fluid. Survivors have significant risk of renal impairment (90%) requiring dialysis or renal transplantation if no fetal intervention is performed. Renal agenesis is the congenital absence of one or both kidneys due to complete failure of the kidney to form. As many as 33% of fetuses with bilateral renal agenesis are stillborn, and the rest of them die immediately after birth due to severe pulmonary hypoplasia. The objective of the serial amnioinfusions for fetuses with these conditions will be to reduce the severity of pulmonary hypoplasia (regenerating the lung functionality) and therefore increase the chance that the newborn survives to begin peritoneal dialysis. Although there is initial evidence that serial amnioinfusions are feasible for the pregnant women and the fetuses, there is still a need to have a prospective clinical trial to confirm the hypothesis that serial amnioinfusions could prevent severe pulmonary hypoplasia allowing the newborns with bilateral renal agenesis or severe LUTO to survive to begin peritoneal dialysis. Therefore, the investigators aim to study the hypothesis that serial amnioinfusions for fetuses with severe LUTO and renal failure and those with bilateral renal agenesis will reduce the severity of pulmonary hypoplasia and therefore increase the chance that the newborn survives to begin peritoneal dialysis.