Vesicoureteral Reflux (VUR)

Introduction

If your child has been diagnosed with vesicoureteral reflux — often shortened to VUR — you are probably trying to make sense of a condition you may never have heard of before. Many parents first learn about VUR after their child has a urinary tract infection (UTI), or after an abnormality is picked up on a scan during pregnancy. The diagnosis can feel worrying, especially when words like “kidney damage” or “surgery” come up in the conversation.

The good news is that VUR is one of the most studied conditions in children’s urology, and for most children it improves on its own as they grow. Even when treatment is needed, there are several effective options, and decisions can usually be made calmly and without rush. This article walks through what VUR is, why it happens, how it is graded, how doctors decide between watchful waiting, antibiotics, and surgery, and what daily life and long-term follow-up usually look like.

The article is written mainly for parents of children with VUR, but the same general principles apply to the much smaller number of adults who are diagnosed with the condition.

What Is Vesicoureteral Reflux?

To understand VUR, it helps to picture the normal plumbing of the urinary tract. The kidneys make urine, which drains down two thin tubes called the ureters — one from each kidney — into the bladder. The bladder stores urine until it is emptied through another tube called the urethra.

In vesicoureteral reflux, that valve does not work properly. When the bladder fills or empties, some urine flows backward (refluxes) up the ureter, and in more severe cases all the way up to the kidney. This matters for two reasons:

• Urine that should be flushed out of the body instead pools in the upper urinary tract. If bacteria are present, they can travel up to the kidney and cause a kidney infection (pyelonephritis).
• Repeated kidney infections, or very high-pressure reflux, can scar the kidney over time and affect how well it works in the long term.

VUR is one of the most common urinary tract conditions in children. It often runs in families: when one child has VUR, siblings and parents have a higher chance of having it too, even without symptoms.

Primary versus secondary VUR

Doctors usually divide VUR into two types based on the cause.

Primary VUR is by far the more common type. The child is born with a ureter that does not enter the bladder at the right angle or length, so the valve mechanism is weak. As the child grows, the tunnel through the bladder wall often lengthens, and the valve gradually starts to work better. This is why so many children outgrow primary VUR without any treatment.

Secondary VUR happens when the reflux is caused by something else going on in the bladder — usually a blockage further down (such as posterior urethral valves in boys) or a bladder that does not store and empty normally because of a nerve problem or learned dysfunctional voiding habits. In secondary VUR, treatment focuses on the underlying problem as much as on the reflux itself.

How VUR Is Graded

VUR is graded on a scale from I to V, based on how high the urine refluxes and how much the ureter and the kidney’s collecting system are stretched. This grading comes from a specific imaging test called a voiding cystourethrogram (VCUG), described later. The grade is one of the most important pieces of information when deciding on treatment.

• Grade I: Urine refluxes only partway up the ureter. The ureter is not dilated.
• Grade II: Urine refluxes all the way up to the kidney, but neither the ureter nor the kidney’s drainage system is stretched.
• Grade III: Urine reaches the kidney and there is mild widening of the ureter and the kidney’s collecting system.
• Grade IV: Moderate dilation. The ureter looks more swollen and slightly kinked, and the kidney’s inner structure is more stretched.
• Grade V: Severe dilation. The ureter is very wide and twisted, and the inside of the kidney is significantly stretched.

In general terms, grades I to III are considered low-grade reflux and tend to resolve on their own. Grades IV and V are high-grade and are more likely to need active treatment. However, grade alone does not decide management. Pediatric urologists also consider the child’s age, sex, history of urinary infections, kidney scarring on scans, bladder and bowel habits, and whether the reflux is on one side or both.

Causes and Risk Factors

Most cases of VUR are not caused by anything the parents did or did not do during pregnancy. The main risk factors are:

• Family history. VUR clusters strongly in families. Siblings of a child with VUR have a meaningfully higher chance of also having it, and children of a parent with a history of VUR are at higher risk too.
• Age and sex. Primary VUR is more often picked up in girls in the toddler and young child years, usually after a UTI. In babies diagnosed before birth on antenatal ultrasound, boys are more often affected.
• Bladder and bowel dysfunction. Older children who hold urine for long periods, have constipation, or have a habit of incomplete bladder emptying can develop secondary reflux or worsen existing reflux.
• Other urinary tract abnormalities. Conditions such as a duplicated ureter, ureterocele, or posterior urethral valves are sometimes associated with VUR.

VUR is not caused by anything in the child’s diet, by toilet training methods, or by any specific parenting behaviour.

How VUR Is Usually Diagnosed

Children typically come to the attention of a urologist or pediatrician along one of two paths.

After a urinary tract infection

A young child with a febrile UTI — a urinary infection with fever — is often investigated for an underlying cause. Current guidance from the American Academy of Pediatrics suggests imaging in children with a first febrile UTI, especially in babies and toddlers. VUR is one of the conditions doctors look for.

On a scan before birth

Many children with VUR are now identified before birth, when a routine antenatal ultrasound shows that one or both kidneys appear swollen (antenatal hydronephrosis). After the baby is born, further scans confirm whether VUR or another condition is the cause.

The main investigations

The tests that confirm or rule out VUR usually include:

• Ultrasound of the kidneys and bladder. A painless scan that shows the size and shape of the kidneys and ureters and looks for swelling or scarring. Ultrasound alone cannot diagnose VUR, but it gives important background information.
• Voiding cystourethrogram (VCUG). This is the standard test for diagnosing and grading VUR. A small soft catheter is passed into the bladder, the bladder is filled with a liquid that shows up on X-ray, and pictures are taken while the bladder fills and while the child passes urine. If urine flows backward into a ureter, that is reflux, and it can be graded.
• Direct radionuclide cystogram (RNC) or contrast-enhanced voiding urosonography. These are alternatives or follow-up tests with lower radiation than a standard VCUG. They are useful for monitoring over time but give less detailed anatomic information.
• DMSA renal scan. A specialised scan that uses a small amount of radioactive tracer to look closely at the kidney tissue itself. It is the most sensitive test for kidney scarring and is often used when high-grade VUR is present or when there have been multiple infections.

The VCUG can be uncomfortable, mostly because of the catheter, and many parents understandably worry about it. Hospitals that perform the test in children take care to use small catheters, gentle handling, and sometimes mild sedation. Talking to your child in age-appropriate language beforehand, and bringing a familiar comfort object, can help.

Treatment and Management

The aim of treatment in VUR is not necessarily to make the reflux disappear on imaging. It is to:

• Prevent kidney infections
• Prevent new kidney scarring
• Preserve long-term kidney function
• Avoid unnecessary procedures in a child who would have outgrown the condition

Because most low-grade VUR resolves spontaneously over several years, much of the decision-making is about how actively to intervene while waiting. Major guidelines from the American Urological Association (AUA) and from the European Association of Urology with the European Society for Paediatric Urology (EAU/ESPU) describe a tiered approach.

Watchful waiting (observation)

For many children with low-grade VUR, especially those who have never had a UTI or whose UTIs are easily controlled, doctors may simply monitor with regular check-ups and periodic scans. Antibiotics are reserved for actual infections. This approach acknowledges that the natural history of low-grade reflux is very favourable.

Watchful waiting tends to be more comfortable when:

• The reflux is low grade (I, II, sometimes III)
• There are no kidney scars on imaging
• The child has had no UTIs, or only one mild UTI
• Bladder and bowel function is normal
• Follow-up is reliable

Continuous antibiotic prophylaxis

This means giving the child a small daily dose of an antibiotic to keep the urine relatively bacteria-free while waiting for the reflux to resolve. The dose is much lower than the dose used to treat an active infection.

Pediatric urologists commonly consider continuous antibiotic prophylaxis when:

• The child is a baby or very young (especially under one year)
• VUR is grade III, IV, or V
• There has been at least one febrile UTI
• There is bladder and bowel dysfunction that is being worked on
• There is existing kidney scarring

Major guidelines describe continuous antibiotic prophylaxis as a reasonable strategy in children at higher risk of recurrent infection, while acknowledging that the evidence does not show benefit for every child. The decision is individualised. Common antibiotics used at low prophylactic doses include trimethoprim, trimethoprim-sulfamethoxazole, and nitrofurantoin (the choice depends on age, allergies, and local resistance patterns).

Parents understandably ask whether daily antibiotics are safe over months or years at low doses. The short answer is that the medicines used at prophylactic doses have a long track record in children, side effects are usually mild, and your child’s doctor will monitor for any problems and reconsider the plan periodically.

Treating bladder and bowel dysfunction

Bladder and bowel habits play a much bigger role in VUR than many parents expect. Constipation, holding urine, hurried voiding at school, and incomplete emptying can all increase pressure in the bladder and make reflux and infections more likely. Treating these issues — with stool softeners, regular toilet times, plenty of fluids, and sometimes pelvic floor or behavioural therapy — is one of the most useful parts of management for toilet-trained children.

Endoscopic injection

An endoscopic injection is a minimally invasive procedure done under anaesthesia. A thin telescope (cystoscope) is passed through the urethra into the bladder, and a small amount of a bulking material (most commonly a substance called dextranomer/hyaluronic acid) is injected just under the opening of the ureter. This lifts and narrows the opening so that the valve mechanism works better.

Endoscopic injection is appealing because:

• It is performed as a day-case procedure with no abdominal cuts
• Recovery is fast — most children are back to normal activity within a day or two
• It can be repeated if needed

The trade-off is that success rates are generally lower than open surgery, particularly for higher grades of reflux, and reflux can sometimes come back after initial success. Pediatric urologists often discuss this option for children with persistent low- to moderate-grade reflux that has not resolved on its own, or where antibiotic prophylaxis has not been enough.

Surgical reimplantation of the ureter

• Open surgery through a small incision in the lower abdomen. This has been performed for many decades and has very high long-term success rates, particularly for higher-grade VUR.
• Laparoscopic or robot-assisted surgery, in which the same operation is done through several small keyhole incisions using a camera and fine instruments. This approach is increasingly used in older children at centres with appropriate experience.

Reimplantation is most often considered when:

• High-grade VUR (IV or V) persists, especially with breakthrough infections
• UTIs keep happening despite antibiotic prophylaxis
• New kidney scarring develops
• There is an associated anatomical problem that needs surgical correction
• The reflux has not resolved by older childhood and the family prefers a definitive solution

Recovery from open reimplantation usually involves a short hospital stay of a few days, a urinary catheter for a brief period, and a return to school within two to three weeks. Bladder spasms are common in the first days and are managed with medication. Long-term success rates are high, and most children do not need further surgery for VUR.

Treating secondary VUR

When VUR is secondary to another problem — such as a blockage at the bladder outlet or a neurogenic bladder — treatment focuses on that problem. This may include relieving an obstruction (for example, fulguration of posterior urethral valves in baby boys), clean intermittent catheterisation, medications to relax the bladder, or surgery to enlarge the bladder. The reflux may improve once bladder pressures are normalised.

How Doctors Choose Between These Options

Parents often ask, “Why is my friend’s child on antibiotics when our doctor wants to operate?” The honest answer is that VUR management is highly individualised. Pediatric urologists weigh up several things at once, including:

• The grade of reflux on both sides
• The child’s age (younger children have more time to outgrow it; babies are also more vulnerable to kidney injury from infections)
• Whether kidney scars are already present
• How many UTIs have occurred and how severe they were
• Whether bladder and bowel dysfunction is present and treatable
• Family preferences and the practicality of long-term follow-up

It is reasonable to ask your child’s doctor why they are recommending a particular path, what the alternatives are, what would change the plan, and what the follow-up schedule will look like.

Recovery After Surgical Treatment

After endoscopic injection

Most children go home the same day. There may be some mild burning when passing urine for a day or two, and rarely a small amount of blood in the urine. Normal activity usually resumes the next day. A follow-up ultrasound is done a few weeks later, and a repeat VCUG is often performed several months afterward to check whether the reflux has resolved.

After open reimplantation

Recovery typically includes:

• A hospital stay of about two to four days
• A urinary catheter for one to several days, depending on the technique used
• Bladder spasms in the first few days, which can be uncomfortable but are well managed with medication
• Pain relief tailored to the child’s age
• Return to school in roughly two to three weeks, avoiding sport and strenuous play for about four to six weeks
• Follow-up ultrasound after a few weeks, with later imaging to confirm long-term success

After laparoscopic or robotic reimplantation

Hospital stay and recovery times are often a little shorter than with open surgery, with smaller scars. The principles of follow-up are the same.

Risks and Complications

Every approach to VUR carries some risks. Discussing these with your child’s urologist is part of an informed decision.

Of the condition itself, if untreated and complicated by infection:

• Recurrent kidney infections
• Kidney scarring
• Reduced kidney function over the long term in a minority of children
• In rare, severe cases, high blood pressure in adulthood or, very rarely, kidney failure

Of continuous antibiotic prophylaxis:

• Mild side effects (rash, stomach upset)
• Development of bacteria that are resistant to the antibiotic being used, which can make a breakthrough infection harder to treat
• Effects on the gut microbiome, the long-term significance of which is still being studied

Of endoscopic injection:

• Failure to fully correct the reflux
• Reflux recurring after initial success
• Rarely, swelling at the ureter opening causing temporary or longer-lasting blockage

Of surgical reimplantation:

• Risks common to any surgery, including bleeding, infection, and reactions to anaesthesia
• Temporary difficulty emptying the bladder
• In a small number of children, partial blockage of the reimplanted ureter, which sometimes needs further treatment
• In a smaller number, reflux on the opposite side that was not previously seen

Daily Life and Self-Management

Most children with VUR live entirely normal lives. There are no special diets, no activity restrictions outside the immediate post-operative period, and no reason to treat them differently at school or at play. A few practical habits help reduce the chance of UTIs and support healthy bladder function:

• Plenty of water. Regular fluids throughout the day keep urine dilute and the bladder flushed.
• Regular toilet trips. Encourage your child to use the toilet every two to three hours during the day, rather than holding for hours, and to take their time to empty fully.
• Manage constipation. A full bowel presses on the bladder and worsens both bladder emptying and infection risk. Fibre, fluids, physical activity, and, where needed, stool softeners are part of routine VUR care.
• Good hygiene. Wiping front to back in girls, and a quick wash after bowel movements, can reduce bacteria around the urethra.
• Watch for UTI symptoms. See below.

Recognising a Urinary Tract Infection at Home

Because UTIs are the main risk in VUR, knowing what to look for is one of the most useful things parents can learn. Symptoms differ by age.

In babies and very young children, UTI may look like:

• Unexplained fever, sometimes with no other obvious cause
• Poor feeding, vomiting, or irritability
• Foul-smelling or cloudy urine
• Failure to grow normally

In older children, UTI usually causes:

• Burning or pain when passing urine
• Needing to pass urine very often or urgently
• Lower tummy pain
• Daytime wetting in a previously dry child
• Fever, back or side pain, and feeling generally unwell (suggesting the kidney is involved)

If your child has known VUR and develops a fever without a clear cause, or any of the symptoms above, it is important to get a urine test promptly so that any infection is treated quickly. Early treatment helps protect the kidneys.

Monitoring and Follow-up

Long-term monitoring is a central part of VUR care, even when no active treatment is being given. A typical follow-up plan includes:

• Periodic ultrasounds to check kidney growth and structure
• Repeat imaging to assess whether reflux has resolved (usually every one to two years for children on observation or prophylaxis)
• DMSA scans if there is concern about new scarring
• Blood pressure checks — raised blood pressure can be an early sign of kidney involvement
• Urine checks during illnesses with fever

The exact schedule is tailored to your child’s grade of VUR, history, and treatment plan. Once reflux has resolved and there has been a stable period without infections, follow-up becomes less frequent. Children with kidney scarring may be followed longer, sometimes into adolescence and adulthood, by a urologist or nephrologist.

Long-term Outlook

The outlook for most children with VUR is very good. Several broad patterns are worth understanding:

• Most children with low-grade VUR (I to III) will see the reflux resolve on its own over several years.
• High-grade VUR (IV and V) is less likely to resolve without intervention, and surgical or endoscopic treatment, when performed, is usually very effective.
• Children whose kidneys are structurally normal at the start and who avoid recurrent infections generally have normal long-term kidney function.
• Children with significant kidney scarring at diagnosis are followed more carefully, because a minority can develop high blood pressure or reduced kidney function later in life. This is part of the reason regular follow-up matters.

VUR and Pregnancy

Some parents of girls with VUR worry about what the diagnosis means for future pregnancies. Most women who had VUR as children go on to have completely healthy pregnancies. Those with significant kidney scarring or reduced kidney function may need closer monitoring of blood pressure and kidney function during pregnancy. This is a useful topic to revisit with a doctor in adolescence and again before planning a pregnancy.

VUR in Adults

Although VUR is largely a pediatric condition, it is sometimes diagnosed in adults, usually after recurrent UTIs or kidney infections. The reasons for reflux in adults are often different from in children — bladder dysfunction, prior surgery, or obstruction are more common contributors. Treatment principles are similar: treating the underlying bladder problem, controlling infections, and considering endoscopic or surgical correction when needed. Decisions are individualised by a urologist.

When to Seek Urgent Medical Care

Contact your child’s doctor or seek urgent care promptly if your child has:

• A fever without obvious cause, especially over 38°C (100.4°F)
• Pain in the side or back along with fever
• Repeated vomiting or refusing fluids
• A baby who is unusually sleepy, floppy, or unwell-looking
• Blood in the urine that is not explained by a recent procedure
• No urine output for an unusually long time

These can be signs of a kidney infection or another problem that benefits from quick assessment.

Frequently Asked Questions

Will my child outgrow VUR?

Most children with low-grade VUR do outgrow it, often over a few years as the bladder grows and the valve mechanism matures. Higher grades are less likely to resolve fully without treatment, but even some grade IV cases improve over time. Your child’s doctor will track progress on imaging.

Does VUR cause pain?

VUR itself usually does not cause pain. Pain in a child with VUR is more likely to come from a urinary infection, bladder spasm, or constipation. Persistent side or back pain should be checked.

Will my other children need to be tested?

Because VUR runs in families, doctors sometimes suggest a screening ultrasound for younger siblings, especially in families where one child has high-grade VUR or kidney scarring. Routine VCUG in siblings without symptoms is not generally recommended. Your child’s urologist can advise based on your specific situation.

Is it safe to keep my child on a low-dose antibiotic for months or years?

The antibiotics used for prophylaxis in VUR have a long track record at the low doses prescribed. Side effects are usually mild, and the plan is reviewed regularly. The main concern is the development of resistant bacteria, which is why doctors balance the benefits against the risks and may stop antibiotics once the child is older or the reflux has resolved.

Will my child need to avoid sports?

Children with VUR do not need to avoid sport or physical activity. After surgery, there is a recovery period of several weeks during which strenuous activity is restricted, but normal play and sport are encouraged once your child is healed.

How long will my child miss school after surgery?

After endoscopic injection, most children return to school within a day or two. After open reimplantation, around two to three weeks is typical, with sport and strenuous activity restricted for a bit longer. Recovery from laparoscopic or robotic surgery is often similar or slightly shorter than open surgery.

Can VUR come back after surgery?

Reflux can recur after endoscopic injection in a minority of children, which is why follow-up imaging is important. Recurrence after open surgical reimplantation is uncommon. Your child’s doctor will plan follow-up scans to confirm long-term success.

Does VUR cause bedwetting?

VUR by itself does not directly cause bedwetting. However, bladder and bowel dysfunction is common in children with VUR, and bedwetting can be part of that picture. Treating bowel and bladder habits often helps both issues.

Should my child eat or drink anything special?

No special diet is required. Plenty of water, a fibre-rich diet to prevent constipation, and regular toilet times are the main practical points.

Will VUR affect my child’s growth or schooling?

The great majority of children with VUR grow and learn normally. Babies with severe VUR and recurrent infections sometimes have early growth concerns, which generally improve with effective treatment.

Conclusion

Vesicoureteral reflux is a common and well-understood condition. For most children, the long-term outlook is reassuring: the reflux improves on its own, infections can be prevented or quickly treated, and the kidneys remain healthy. For children who need more active treatment, several effective options exist, from a small daily antibiotic to endoscopic injection to definitive surgical repair. The right path depends on the grade of reflux, the child’s age and history, the state of the kidneys, and the family’s preferences, and is best worked out together with a pediatric urologist who can tailor the plan over time. Whatever path your family takes, careful follow-up — checking on the kidneys, watching for infections, and supporting healthy bladder and bowel habits — is the thread that holds long-term care together.