What are Undescended Testicles (Cryptorchidism)?

What Happens under Normal Conditions?

How the testicles descend into the scrotum during pregnancy
How the testicles descend into the scrotum during pregnancy
Image © 2003 Fairman Studios, LLC.

The testicles (or "testes") are 2 organs that hang in a pouch-like skin sac (the scrotum) below the penis. The testicles are where sperm and testosterone (the male sex hormone) are made. The scrotum keeps the testicles in a cooler setting than the body. This is because sperm can't grow at body temperature. During childhood, sperm in the testicles go through a process that results in mature sperm at puberty.

Normal testicles form early in a baby boy's growth. They form in the lower belly (abdomen), but descend, or "drop," into the scrotum toward the end of pregnancy. Normal testicles attach themselves with stretchable tissue in the bottom of the scrotum. This is controlled by the baby's normal hormones.

What are Undescended Testicles?

An undescended testicle (or "testis") is when it fails to drop into the normal place in the scrotum. Your child's health care provider can find this during a routine exam. This issue is found in about 3 or 4 out of  100 newborns (and up to 21 out of 100 premature newborns). Luckily, about half of these testicles will drop on their own during the first 3 months of life. But testicles won't drop on their own after 3 months of age. Thus, about 1 or 2 out of 100 boys with undescended testicles will need treatment.

It's important not to confuse undescended testicles with "retractile" testicles. After 6 months of age, a male child has a reflex that temporarily pulls the testicles up to protect them when he's cold or frightened. These testicles are in the scrotum at other times and don't need treatment. Only testicles that are truly undescended need treatment. A pediatric urologist can tell the difference with a physical exam.

The testicles need to be 2 to 3 degrees cooler than normal body temperature to make sperm. The scrotum is many degrees cooler than body temperature, and so is the ideal place for the testicle. Testicles that don't drop into the scrotum won't work normally. The longer the testicles are too warm, the lower chances are that the sperm in that testicle will mature normally. This can be a cause of infertility, especially when both testicles are affected.

Undescended testicles are also linked to a higher risk of:

  • Testicular cancer in adulthood (though the risk is still less than 1 in 100)
  • Testicular torsion (twisting of the chord that brings blood to the scrotum)
  • Developing a hernia near the groin


What Causes Undescended Testicles?

In most children with this health issue, it's not known why the testicles fail to drop. It may be because the testicles aren't normal to start with. In other cases, there's a mechanical problem. The testicles drop but miss the scrotum, ending up next to the scrotum instead. These are called "ectopic testicles." Or it may be that the baby's hormones can't stimulate the testicles normally. No studies have shown that the problem is caused by something the mother did or ate during pregnancy.

Sometimes the testicles drop but don't attach in the scrotum. Then, when the boy grows, it becomes clear that the testicles aren't attached. About 1 of every 5 cases of undescended testicles are found once the boy is no longer a baby. For this reason, all boys should have the location of their testicles checked during each annual physical exam.



How are Undescended Testicles Diagnosed?

A testicle that can't be felt in a physical exam is called "nonpalpable." Nonpalpable testicles may be in the abdomen (undescended), absent, or very small ("atrophic"). It's important to find out whether there is a testicle that hasn't dropped. An undescended testicle left inside the abdomen could form a tumor later in life. Such a tumor might not be noticed until it becomes quite large or causes symptoms. Unfortunately, there's no test, such as an ultrasound, that can definitively show whether a testicle is there. Surgery is the only way to find out for sure.

Pediatric urologists are experts in both open and laparoscopic surgery. Laparoscopy is surgery done through thin tubes put into your child's body through a small cut. The surgeon uses a special camera to see inside your child's body. The surgeon will find one of 3 situations:

  1. Blind-ending testicular blood vessels – proving there's no testicle
  2. Vessels leaving the abdomen – proving there's no testicle in the abdomen
  3. A testicle in the abdomen. If a testicle is found, it's brought down into the scrotum or removed, based on its condition.


How are Undescended Testicles Treated?

The testicle won't drop after 3 months of age, so the only treatment choice is surgery. Surgery is recommended after 6 months of age. The timing takes into account when the child is able to handle anesthesia and the surgery. Drugs or hormone treatment aren't useful.

This surgery is called an orchiopexy. The child is put under (general anesthesia) for this surgery. Almost always the child can go home the same day and is back to normal within 1 to 2 days. A cut about 1 inch long is made in the groin area (most often it can hardly be seen later). The testicles is freed from all nearby tissues so that it moves easily into the scrotum. Then it is stitched into place. If there's a hernia, it's fixed at the same time. In some cases, the testicle is too high for this simple surgery. If this is the case, more complex methods (and sometimes even 2 surgeries) are needed. Overall, the success rate with surgery is 98 out of 100.



What Can I Expect after Treatment?

After treatment, the testicle often grows to normal size in the scrotum. In some cases, the testicle wasn't normal to start with, and never grows the right way. In other cases, sperm never grow, even though the testicle size is normal. In most cases, after treatment for 1 undescended testicle, fertility becomes normal and the chances of fathering a child in the future are high. When the child becomes a teen, he should have routine physical exams and do monthly testicular self-exams. Routine physicals will look for signs of testicular cancer, which remains a slight risk.



More Information

Frequently Asked Questions

Is an undescended testicle always found in babies?

No. About 1 of every 5 cases of undescended testicles are found after the boy is no longer a baby. The testicles of these boys appeared to have dropped normally as babies. If an undescended testicle appears later it is called an "ascending testicle." This happens because the testicle doesn't "fix" itself in the scrotum, and is noticed as the child grows. Often these boys are known to have a retractile testicle before they are diagnosed with an ascending testicle. These testicles need surgery to move them into the scrotum. Sperm won't mature if the testicle stays undescended. For these reasons, boys should have their genitals checked during their yearly physical exam.