KidsMD Health Topics


  • Overview

    Megaureter is simply the medical term for a "large" or "big" ureter.

    • The ureter is a tube-like structure that serves as the passageway for the flow of urine from the kidney to the bladder.
    • There are two ureters, one for each kidney.
    • Together, the ureter and the kidney collecting system are referred to as the upper urinary tract.

    The Department of Pediatric Urology at Boston Children's Hospital is recognized internationally and is staffed by experienced physicians, who are teachers, leaders and innovators, dedicated to state of the art urologic care, surgical expertise and research in all aspects of pediatric urology.


    Boston Children's Hospital 
    300 Longwood Avenue
    Boston MA 02115


  • In-Depth

    What causes a megaureter?

    There may be different causes for a megaureter, including:

    • A congenital (present at birth) condition in which the distal ureter (the final or bottom part of the ureter), which is normally a muscular layer of tissue, is replaced by stiff, fibrous tissue. With no muscle, normal peristalsis (worm-like movement of the ureter that propels urine towards the bladder) cannot occur.
    • High-grade vesicoureteral reflux (when your child urinates, some urine travels back up the ureter and possibly up to the kidney)

    What are the symptoms of megaureter?

    There's a good chance that your child will not show any symptoms of megaureter. More and more often, it is detected on prenatal ultrasound. But sometimes a child is referred to a pediatric urologist or pediatric surgeon after experiencing at least one of the following symptoms during infancy or early childhood:

  • Tests

    How is megaureter diagnosed?

    If your child has megaureter, doctors must look for what's causing it and that is what will determine the course of treatment. So if your child has been referred to a specialist and megaureter is suspected, there will be a complete evaluation of the entire urinary tract. Megaureter may be detected during an initial evaluation that includes an ultrasound of the kidneys, ureters and bladder. Other studies are usually needed to confirm the diagnosis and to determine the cause. These may include:

    • intravenous pyelogram (IVP), which allows doctors to see the anatomy of the ureter and assess how well your child's kidneys collect and drain urine. This test also allows doctors to estimate the diameter (width) of the ureter. In general, megaureter is a ureter with a diameter of more than seven to ten millimeters.
    • voiding cystourethrogram (VCUG) This specialized x-ray is used if the doctor suspects that vesicoureteral reflux (backward flow of urine from the bladder to the ureter and/or kidney) is causing the problem.
    • A renal (kidney) scan is used if the doctor suspects an obstruction at the ureterovesical junction (where the ureter meets the bladder). This scan provides very detailed information about kidney function. Along with the IVP, it is particularly helpful in identifying and assessing the degree of blockage in this kind of obstruction.

    Once the doctor has checked for vesicoureteral reflux and obstruction, he or she will assign your child's megaureter or dilated upper urinary tract into one of the four following categories:

    1. refluxing megaureter: Vesicoureteral reflux alone is responsible for the megaureter.
    2. obstructed megaureter: Significant blockage the ureterovesical junction (UVJJ) alone is responsible.
    3. refluxing and obstructed megaureter: Both vesicoureteral reflux and blockage at the UVJ are present.
    4. nonrefluxing and nonobstructed megaureter: The upper urinary tract is dilated (wider than normal) but no evidence of reflux or clinically significant obstruction can be determined.

    Even after the cause of your child's megaureter is determined, the doctor may want to perform additional tests to get a more complete picture of kidney and bladder function. These tests may include:

    • specialized renal scans and/or laboratory (blood and urine) tests
    • baseline serum creatinine level - this estimates kidney function and is essential for follow-up care, especially if your child has bilateral megauters (both ureters are affected).
    • urodynamic evaluation - these tests measure how well the bladder stores and empties urine.
  • Your Story

    Ureter reimplantation and megaureter repair

    My son, Luke Dangel, was admitted to Children’s Hospital Boston last September for ureter reimplantation and megaureter repair on his left side, which, while routine surgery at Children’s, was understandably scary and intimidating for us. Beyond the obvious skill and competence of everyone who interacted with Luke during his subsequent seven-day recovery, my husband and I were fully impressed and incredibly grateful for the compassion and care we received.

    I recently attended the Pioneering Change symposium at Harvard Medical School, and I was especially moved by a speech about the importance of doctors taking the time to really listen to patients, and to understand and address patient/family concerns. Richard Lee, MD, of your Urology Department, was amazing not only in his technical skill as a surgeon, but also his bedside manner. Throughout Luke’s stay, Dr. Lee was attentive, committed, compassionate and eager to make sure Luke—and his parents—were as comfortable as possible. Dr. Lee modeled this behavior for his residents, who were also very attentive and solicitous towards both him and us.

    Beyond Dr. Lee and the residents, I can’t say enough about the nurses and staff of 8 West. Almost without exception, people were kind, caring, attentive and incredibly competent. I just wanted to take a moment to acknowledge the amazing care we received at Children’s. We are very grateful.


    Carolyn Lyons

Request an Appointment

If this is a medical emergency, please dial 9-1-1. This form should not be used in an emergency.

Patient Information
Date of Birth:
Contact Information
Appointment Details
Send RequestIf you do not see the specialty you are looking for, please call us at: 617-355-6000.International visitors should call International Health Services at +1-617-355-5209.
Please complete all required fields

This department is currently not accepting appointment requests online. Please call us at: 617-355-6000. International +1-617-355-6000.

This department is currently not accepting appointment requests online. Please call us at: 617-355-6000. International +1-617-355-6000.

Thank you.

Your request has been successfully submitted

You will be contacted within 1 business day.

If you have questions or would like more information, please call:

617-355-6000 +1-617-355-6000
Find a Doctor
Search by Clinician's Last Name or Specialty:
Select by Location:
Search by First Letter of Clinician's Last Name: *ABCDEFGHIJKLMNOPQRSTUVWXYZ
Condition & Treatments
Search for a Condition or Treatment:
View allSearch
The future of pediatrics will be forged by thinking differently, breaking paradigms and joining together in a shared vision of tackling the toughest challenges before us.”
- Sandra L. Fenwick, President and CEO