My unborn baby boy has unilateral hydronephrosis. what is this?

Not to worry: Your baby will have an ultrasound after birth to see if it is still there.This is a finding I read a lot on prenatal ultrasound reports. So far none in my experience have had it after birth even though they were all thought to have it prenatally. It means the kidney on the affected side has developed an appearance suggestive of back up fluid and pressure on it as if something is blocking the flow of urine from the kidney to the bladder.