Pyelectasis

What is pyelectasis?

Pyelectasis is an increased buildup of urine (pee) inside the central part of a fetus’ kidney. This buildup is due to a blockage that prevents pee from traveling from the kidneys to the ureter and bladder. In other cases, it may be due to reflux of urine in the opposite direction from the bladder to the kidneys (urinary reflux).

Depending on the location of the urine buildup, healthcare providers may call the condition pyelectasis, pelviectasis, pelvocaliectasis or caliectasis.

Pyelectasis vs hydronephrosis: What’s the difference?

Both terms refer to kidney swelling caused by a buildup of pee. With fetal pyelectasis, blockage is mild, so less pee collects in the kidney. This results in a slight enlargement in the central area of the kidney. With fetal hydronephrosis, blockage is more severe. In the most severe cases, this results in ballooning of the kidney.

Most of the time, pyelectasis will go away on its own. But in about 10% of cases, pyelectasis worsens and becomes hydronephrosis. If this happens, the fetus might need further testing and monitoring by a pediatric nephrologist or pediatric urologist.

How common is pyelectasis?

Pyelectasis is relatively common. Around one in every 40 pregnancies involve pyelectasis. The condition may affect one kidney (unilateral pyelectasis) or both kidneys (bilateral pyelectasis).

How much more common is pyelectasis in males?

Pyelectasis is approximately three times more common in male fetuses.

Is pyelectasis serious?

In most cases, pyelectasis won’t have a significant negative impact on your baby. The majority of babies with pyelectasis are born healthy and do quite well.

Rarely, pyelectasis will develop into severe hydronephrosis. If this happens, your healthcare provider might recommend fetal surgery to prevent damage to your baby’s kidneys.

Is pyelectasis a marker for Down syndrome?

If pyelectasis is visible on an ultrasound, there’s an increased chance that the fetus could have Down syndrome. However, most fetuses with pyelectasis don’t have Down syndrome.

In fact, as long as pyelectasis isn’t accompanied by abnormal blood tests or other ultrasound irregularities, the condition is usually viewed as a normal variation in fetal development.

What are the symptoms of pyelectasis?

Pyelectasis during pregnancy usually doesn’t cause any noticeable symptoms. The issue is typically detected through routine prenatal ultrasounds.

What causes fetal pyelectasis?

There are two main causes of pyelectasis: ureteropelvic junction obstruction and vesicoureteral reflux.

Ureteropelvic junction obstruction

Ureteropelvic junction obstruction happens when there’s a blockage where the fetus’ ureter attaches to the kidney. This causes the pee to stay trapped inside the kidney instead of flowing out to the ureter. The obstruction causes pressure inside the kidney, which could result in pyelectasis and eventual decline of kidney function.

Vesicoureteral reflux

Pee should leave the kidneys, move through the ureters and end up in the bladder. It’s then stored in the bladder until it leaves the fetus’ body and becomes part of the amniotic fluid. In some cases, however, pee backs up from the bladder and goes back into the ureters and sometimes the kidneys. When this happens, it’s called vesicoureteral reflux. If the pee stays trapped in the kidney long enough to cause swelling, then it could result in pyelectasis.

How is pyelectasis diagnosed?

Healthcare providers diagnose pyelectasis during a prenatal ultrasound. If your ultrasound shows pyelectasis, then you’ll need additional monitoring during your pregnancy.

How is pyelectasis treated?

In most cases, pyelectasis resolves on its own without treatment. Your healthcare provider will simply monitor the condition throughout your pregnancy. If necessary, a pediatric urologist or nephrologist will examine your baby after delivery. In some instances, a pediatric urologist may perform a pyeloplasty — a surgical procedure that eliminates a blockage between the kidney and ureter.

If pyelectasis or hydronephrosis becomes so severe that kidney damage is possible during pregnancy, then your provider may recommend fetal surgery. This is uncommon.

How can I reduce my baby’s risk for pyelectasis?

Pyelectasis is a variation of fetal development, so there’s no way to prevent the condition. But regular ultrasounds during your pregnancy are essential. This way, your healthcare provider can monitor your situation and recommend treatment when and if it becomes necessary.

What can I expect if my baby has pyelectasis?

If your healthcare provider finds pyelectasis on an ultrasound, then there’s a good chance you’ll just need monitoring during your pregnancy and after birth. Your provider will take regular ultrasounds to make sure the blockage doesn’t become severe.

If pyelectasis worsens and becomes hydronephrosis, then you’ll likely need to visit a pediatric urologist or pediatric nephrologist once your baby is born. They’ll examine your baby and determine if treatment is necessary.

In rare cases, the blockage from pyelectasis can become so severe that kidney damage is possible while the fetus is still in the womb. If this is a concern, your healthcare provider will talk to you about fetal surgery to correct the condition.

Can pyelectasis be cured?

Yes. In over 90% of cases, pyelectasis goes away on its own. If the blockage is more severe, then surgery may be necessary to correct the problem.

Fetuses with severe hydronephrosis are more likely to have problems that persist after delivery. In these cases, your baby may need surgery.

When should I see my healthcare provider?

It’s important to see your healthcare provider for routine checkups and imaging. They can only diagnose pyelectasis with an ultrasound. They’ll keep a close eye on your progress and recommend treatment if it’s necessary.

What questions should I ask my healthcare provider?

Here are some questions you can ask your healthcare provider if they found pyelectasis on an ultrasound:

• Is there blockage, and if so, where is it located?
• Is there urinary reflux?
• Is the blockage mild, moderate or severe?
• Is there anything else on my ultrasound or anything in my bloodwork that indicates my baby could have Down syndrome or another chromosomal condition?
• How likely is it that my baby will need surgery?

A note from Cleveland Clinic

Hearing that your baby has pyelectasis can be scary and unsettling. But in most cases, monitoring is all that’s necessary. Your healthcare provider will run a combination of tests to see if pyelectasis is the only issue, or if it’s an indication of another condition. They’ll keep a close eye on your progress and work with you every step of the way.