Urine Blockage in Newborns

The urinary tract consists of

We rely on our kidneys and urinary system to keep fluids and natural chemicals in our bodies balanced. While a baby is developing in the mother's womb, much of that balancing is handled by the mother's placenta. The baby's kidneys begin to produce urine at about 10 to 12 weeks after conception, but the mother's placenta continues to do most of the work until the last few weeks of the pregnancy. Wastes and excess fluid are removed from the baby's body through the umbilical cord. The baby's urine is released into the amniotic sac and becomes part of the amniotic fluid. This fluid plays a role in the baby's lung development.

Sometimes, a birth defect in the urinary tract will block the flow of urine in an unborn baby. As a result, urine backs up and causes the ureters and kidneys to swell. Swelling in the kidneys is called hydronephrosis. Swelling in the ureters is called hydroureter.

Hydronephrosis is the most common problem found during ultrasound examination of babies in the womb. The swelling may be barely detectable or very noticeable. The results of hydronephrosis may be mild or severe, but the long-term outcome for the child's health cannot always be judged by the severity of swelling. Urine blockage may damage the developing kidneys and reduce their ability to filter. The blockage may also raise the risk that the child will develop a urinary tract infection (UTI). Recurring UTIs can lead to more permanent kidney damage. In the most severe cases of urine blockage, the amniotic sac is so reduced that the lack of fluid threatens the baby's lung development.

Types of Defects in the Urinary Tract

Hydronephrosis can result from many types of defects in the urinary tract. Doctors use specific terms to describe the type and location of the blockage.

Syndromes That May Affect the Urinary Tract

In addition to defects that occur in a single spot in the urinary tract, some babies are born with genetic conditions that affect several different systems in the body. A condition that includes multiple, seemingly unrelated problems, is called a syndrome.


Birth defects and other problems of the urinary tract may be discovered before the baby is born, at the time of birth, or later, when the child is brought to the doctor for a urinary tract infection or urination problem.

Prenatal Screening

Tests during pregnancy can help determine if the baby is developing normally in the womb.

Examination of Newborn

Sometimes a newborn does not urinate as expected, even though prenatal testing showed no sign of urine blockage. The baby may urinate only small amounts or not at all. An enlarged kidney may be felt during the newborn examination as well. Different imaging techniques are available to determine the cause of the problem.

Later Diagnosis

Sometimes urine blockage is not apparent until the child develops the symptoms of a urinary tract infection. These symptoms include

If these symptoms persist, the child should be seen by a doctor. For any fever in the first 2 months of life, the child should be seen by a doctor immediately. The doctor will ask for a urine sample to test for bacteria. The doctor may also recommend imaging tests including ultrasound, VCUG, or nuclear scan.


Treatment for urine blockage depends on the cause and severity of the blockage. Hydronephrosis discovered before the baby is born will rarely require immediate action, especially if it is only on one side. Often the condition goes away without any treatment before birth or sometimes after. The doctor will keep track of the condition with frequent ultrasounds. With few exceptions, treatment can wait until the baby is born.

Prenatal Shunt

If the urine blockage threatens the life of the unborn baby, the doctor may recommend a procedure to insert a small tube, called a shunt, into the baby's bladder to release urine into the amniotic sac. The placement of the shunt is similar to an amniocentesis, in that a needle is inserted through the mother's abdomen. Ultrasound guides the placing of the shunt. This fetal surgery carries many risks, so it is performed only in special circumstances, such as when the amniotic fluid is absent and the baby's lungs aren't developing or when the kidneys are very severely damaged.


Antibiotics are medicines that kill bacteria. A newborn with possible urine blockage or VUR may be given antibiotics to prevent urinary tract infections from developing until the urinary defect corrects itself or is surgically corrected.


If the urinary defect doesn't correct itself and the child continues to have urine blockage, surgery may be needed. The decision to operate depends upon the degree of blockage. The surgeon will remove the obstruction to restore urine flow. A small tube, called a stent, may be placed in the ureter or urethra to keep it open temporarily while healing occurs.

Intermittent Catheterization

If the child has urine retention because of nerve disease, the condition may be treated with intermittent catheterization. The parent, and later the child, will be taught to drain the bladder by inserting a thin tube, called a catheter, through the urethra to the bladder. Emptying the bladder in this way helps prevent kidney damage, overflow incontinence, and urinary tract infections.