Antenatal hydronephrosis is dilation with urine of the upper urinary tract (kidneys and ureter tubes) seen on ultrasound testing on an unborn baby during pregnancy. Most expecting mothers today will have at least one ultrasound before having their baby, and in approximately 1% of cases, some dilation of the urinary tract is seen on these tests. The list of causes is long, but dilation of urinary collecting systems is usually caused by one of four things: the urine is having trouble getting out of the kidneys or ureter tubes (obstruction), the urine is being forced back up in the kidneys or ureter tubes (vesicoureteral reflux), the bladder muscle is not functioning properly due to neurologic issues (neurogenic bladder) or the urinary tract simply looks that way even though everything is draining well in the correct direction. Thankfully, most hydronephrosis detected prior to birth is mild and usually not related to any problem. Sometimes, however, additional treatment or surgery may be needed. Your urologist’s job is to help you determine if anything could be causing these problems and, if so, to help determine how best to treat your child.
Most babies with AH will undergo some initial testing ordered by your pediatrician or neonatologist, or as recommended by your pediatric urologist. These tests may include imaging studies, urine and/or blood tests. If your child has antenatally detected hydronephrosis, your pediatric urologist will work with you to develop a detailed individualized care plan for your child.