By: Hatim Thaker, MD, FAAP
Before birth, a baby boy's testes (testicles) develop inside the abdomen. Closer to delivery, these organs travel through a canal in the groin. When all goes as it should, the testicles then fall into place in the scrotum, the bag of skin beneath the penis.
In some boys, especially those who are born premature, one or both testicles do not make it down to the scrotum before birth. This is known as cryptorchidism, more commonly called undescended testicles. For babies born with this condition, the testicles sometimes descend on their own—usually by six months of age. In other cases, treatment or surgery is needed.
Are undescended testicles common in children?
Undescended testicles is the most common genital abnormality found at birth. About 1-3% of full-term boys have the condition at birth. But the rate is much higher in boys born preterm. About 30% of boys with a low birthweight (less than 5 pounds, 4 ounces) are born with undescended testicles. Those with a very low birthweight (less than 3 pounds, 4 ounces) have a near 100% chance of being born with undescended testicles.
What causes undescended testicles?
Nobody is certain what causes undescended testicles. Premature birth plays a role, but the condition may also be genetic. There is a 7.5% chance that a brother of a boy with undescended testicles will have the same condition. The odds rise to 25% if the brother is an identical twin.
What are symptoms of undescended testicles?
Typically, boys with undescended testicles have no symptoms of pain or discomfort. The scrotum may appear small and underdeveloped. If only one testicle is undescended, the scrotum may look asymmetrical (full on one side, empty on the other). You may also notice that the testicles are sometimes in the scrotum and at other times absent (for example, when he is cold or excited). This is a condition known as retractile testicles.
Are there different types of undescended testicles?
Among boys with undescended testicles, there are several different forms of the condition:
Congenital: A testicle that never descended into the scrotum. This is diagnosed at birth.
Acquired: When the testicle was within the scrotum at birth, but are later is abnormally positioned testicle.
Vanishing testicle: When a testicle is completely absent--neither in the scrotum or the abdomen—it is called a vanishing testicle. Having a single testicle typically causes no hormonal or fertility problems.
Retractile testicle: With this condition, a testicle is truly located in the scrotum but slips up into an abnormal position (such as the groin). This is typically caused by a muscle reflex. Cold temperatures, for example, can prompt this normal reflex and cause the testicle to temporarily disappear. A retractile testicle often does not require surgical treatment.
How are undescended testicles diagnosed?
Undescended testicles are diagnosed through physical examination. At every well-child visit, the doctor will do a genital examination to check the location of the testicles.
Does my child need an ultrasound to locate his testicle?
Usually not. Most often, an undescended testicle diagnosis can be confirmed with a careful physical exam by your child's doctor. Ultrasound typically is not necessary, even in situations where the testicle cannot be felt in the groin. In fact, an ultrasound may give inaccurate results on the location or presence/absence of a testicle.
Only in very rare cases is ultrasound helpful, such as before surgery for a previously repaired undescended testicle.
How are undescended testicles treated?
If your child's testicle has not come down into the scrotum on its own by 6 months of age, they will likely need treatment. It is relatively rare for undescended testicles to fall into proper position after 6 months of age. So, there is usually little value to waiting.
In the past, undescended testicles were treated with hormone injections; however, this is no longer recommended. Instead, the current approach to treatment involves surgery to relocate the testicle into the scrotum. This surgical procedure is called an orchiopexy. It may need to be performed in a two-stage manner depending on the location of the testicle.
The goals of this surgery include:
Relocate the testicle into a natural position in the scrotum.
Reduce the risk of potential hormone and fertility problems.
Reduce the risk of testicular cancer, which is slightly raised if testicles are undescended.
Complications of orchiopexy are very rare. It can be performed as an outpatient procedure.
When should my child have the surgery to correct an undescended testicle?
Since the chances of the testicle coming down on its own is slim after 6 months old, your child should be referred for treatment once they've reached that age. Waiting beyond 2-3 years may hinder the testicle's ability to grow and function normally. Ideally, orchiopexy should be done within the first 18 months of life.
As with any surgical procedure, the risks of anesthesia should be carefully considered for your child's specific situation.
For teenagers with an undescended testicle that has never been fixed, your specialist may suggest biopsy of the testicle to look for cancerous cells.
What if the testicle is twisted?
In some cases, the undescended testicle may be twisted, in a condition called testicular torsion. As a result, its blood supply may be stopped, causing pain in the inguinal (groin) or scrotal area. If this situation is not corrected promptly, the testicle can be damaged severely and permanently. If your child has an undescended testicle and complains of pain in the groin or scrotal area, call your pediatrician or go to a hospital emergency department immediately.
Who is involved in the medical care for a child with undescended testicles?
Pediatricians and pediatric urologists work together to care for boys with undescended testicle. Boys who may need surgery are referred to a pediatric urologist.
About Dr. Thaker
Hatim Thaker, MD, FAAP, is a Fellow of Pediatric Urology at Boston Children's Hospital/Harvard Medical School. He completed his residency training at the University of Southern California/LA County Medical Center. Dr. Thaker has a research interest in urinary incontinence and neurogenic bladder and is engaged in developing novel therapeutics. Within the American Academy of Pediatrics, he is a member of the Section on Urology.