There are several different birth defects that affect the bladder Bladder The bladder is an expandable, muscular sac. Urine accumulates in the bladder as it arrives from the ureters. The bladder gradually increases in size to accommodate an increasing volume of urine... read more (the expandable, muscular sac that holds urine). Some are apparent at the doctor's examination. Others require tests to evaluate the urinary tract Evaluation of Kidney and Urinary Tract Disorders A doctor obtains a medical history by interviewing a person. The interview includes questions about a person's symptoms, past medical history (what disorders the person has had), drugs (prescribed... read more .
(See also Overview of Urinary Tract Birth Defects Overview of Kidney and Urinary Tract Birth Defects Birth defects are more common in the kidney and urinary system (urinary tract) than in any other system of the body. Defects can develop in the Kidneys—the two organs that filter waste from... read more .)
A Look Inside the Urinary Tract
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Problems with nerves to the bladder (neurogenic bladder Neurogenic Bladder Neurogenic bladder is lack of bladder control because of a nerve problem such as a stroke, spinal cord injury, or tumor. Uncontrollable loss of urine (urinary incontinence) is the primary symptom... read more )
Birth defects that affect the nerves to the bladder, particularly spinal cord defects such as spina bifida Spina Bifida Neural tube defects are a certain type of birth defect of the brain, spine, and/or spinal cord. Neural tube defects can result in nerve damage, learning disabilities, paralysis, and death. The... read more , cause problems in several ways:
Flaccid bladder: The nerve problem makes the bladder muscles limp and weak (flaccid). The bladder cannot contract properly to empty itself, so urine tends to fill up the bladder at low pressure.
Spastic bladder: The nerve problems cause the bladder to contract too much (spastic), and urine in the bladder is at high pressure. The bladder is small.
In some children, the bladder is sometimes flaccid and at other times spastic.
If children cannot empty their bladder completely, urine can become stagnant, which increases the risk of urinary tract infections Urinary Tract Infection (UTI) in Children A urinary tract infection is a bacterial infection of the urinary bladder ( cystitis), the kidneys ( pyelonephritis), or both. Urinary tract infections are caused by bacteria. Infants and younger... read more (UTIs) or formation of bladder stones Stones in the Urinary Tract Stones (calculi) are hard masses that form in the urinary tract and may cause pain, bleeding, or an infection or block of the flow of urine. Tiny stones may cause no symptoms, but larger stones... read more . Also, the full bladder may overflow, resulting in involuntary release of urine (called urinary incontinence Urinary Incontinence in Children Urinary incontinence is defined as the involuntary release of urine occurring two or more times per month after toilet training has been completed. Incontinence may be present During the day... read more ). If the child's bladder cannot empty completely, the bladder is drained by inserting a thin, flexible tube (catheter) through the urethral opening into the bladder. This process is called catheterization. Catheterization is repeated several times each day because it is better to remove the catheter as soon as the urine has finished draining. This process is called intermittent catheterization. However, sometimes the catheter must be left in all the time.
If catheterization does not work, a surgical procedure called a vesicostomy may be done. In this procedure, doctors make an opening between the abdominal wall and the bladder. Urine drains from the bladder through the opening into a diaper. An alternative to vesicostomy is to create a channel or tunnel between the bladder and the skin. A catheter can be placed in this channel.
If the urine is under high pressure, the urine may flow backward from the bladder into the kidneys (urinary reflux Urinary Reflux Urinary reflux is when urine flows backward from the bladder into the ureter and sometimes the kidney, usually because of a birth defect of the urinary tract. Each kidney continuously filters... read more ). Urinary reflux may cause recurring urinary tract infections, kidney damage, or both. Children who have a small bladder and increased bladder pressure may be given drugs to relax the bladder muscles or may be catheterized. If these measures do not work, doctors may do surgery to help decrease the involuntary release of urine and decrease bladder pressure so the kidneys do not become damaged. Some surgical procedures increase the size of the bladder. However, after surgery, children usually still need catheterization.

Failure of the bladder to close properly
When the bladder is first developing in the fetus, it normally closes to form a muscular sac. Rarely, the bladder does not completely close and it opens out onto the surface of the abdomen (called bladder exstrophy), allowing urine to drip through the abdominal wall rather than out the urethra. Children who have bladder exstrophy may also have an abnormally formed urethra and external genital organs (penis Structure of the Male Reproductive System The male reproductive system includes the penis, scrotum, testes, epididymis, vas deferens, prostate, and seminal vesicles. The penis and the urethra are part of the urinary and reproductive... read more , testes Structure of the Male Reproductive System The male reproductive system includes the penis, scrotum, testes, epididymis, vas deferens, prostate, and seminal vesicles. The penis and the urethra are part of the urinary and reproductive... read more , or clitoris Female External Genital Organs The external genital structures include the mons pubis, labia majora, labia minora, and clitoris. The area containing these structures is called the vulva. The external genital structures have... read more ) and sometimes abnormalities of the anus Anorectal Malformations Anorectal malformations are birth defects in which the opening of the anus is narrow, covered with skin, or missing. Infants may develop intestinal obstruction. The diagnosis is based on a physical... read more .
A similar disorder involves the connection between the bladder and the bellybutton (umbilicus) that is present when the fetus is first developing. This connection is called the urachus. Normally this connection closes before birth. If this connection remains open (called a patent urachus), urine drains out of the bellybutton.
In both disorders, infants are at risk of urinary tract infections. Doctors do surgery to close the abnormal openings and repair the bladder if needed. Surgery may be done shortly after birth or may be delayed.
Bladder diverticulum
Sometimes children are born with an outpouching (diverticulum) in the wall of the bladder. Urine can stagnate in these diverticula and cause urinary tract infections. Doctors sometimes do surgery to remove the diverticulum and reconstruct the bladder wall.