What happens under normal conditions?
Normal testicles (testes) arise early in a boy's development. Although they are located initially in the abdominal cavity, they gradually descend into the scrotal area during the latter part of pregnancy, in response to the baby's normal hormones. The testicles in the infant make hormones primarily. After puberty, they produce both hormones and sperm.
What are undescended testicles and how are they diagnosed?
In children with an undescended testicle (testis), the testicle fails to reach the normal position in the scrotum. This condition is obvious on routine examination in the infant and is present in about 3% of newborns (and up to 21% of premature newborns). Fortunately, about three-quarters of these testicles will descend spontaneously during the first three months of life. Because it is thought that testicles will not descend spontaneously after three months of age, about 0.8% of boys will need treatment. It is extremely important not to confuse undescended testicles with "retractile" testicles. After six months of age, normal babies have a reflex that pulls the testicles up to protect them when he is cold or frightened. These testicles are in the scrotum at other times and do not require any treatment. An expert physical examination may be needed to distinguish these, and it is important, as only truly undescended testicles need treatment.
The testicles function better at a temperature slightly lower than normal body temperature. This is especially true for the part of the testicle that makes sperm. Fortunately, the scrotum is several degrees cooler than the main body temperature and hence is the ideal location for the testicle. Testicles that do not descend into the scrotum are not likely to function normally. Because they may not make sperm, they can be a cause of infertility, especially when both testicles are affected. They are also associated with a higher risk of testicular cancer in adulthood (although the risk is still less than one in 100). Many times there is also an associated hernia when the testicles fail to descend normally.
What causes undescended testicles?
In most children with this condition it is not known why the testicles fail to descend. It may be because the testicles are not normal to start with. In other cases there is a mechanical problem that leads them in a wrong direction (these are called "ectopic testicles"). Or, it may be that the infant's hormones may be insufficient to stimulate the testicles normally. It is important, however, to realize that there are no studies showing that the problem is caused by anything that the mother did or ate during pregnancy.
What if the testicle cannot be felt on physical examination?
A testicle that cannot be felt on physical examination is called "nonpalpable." Nonpalpable testicles may be located in the abdomen, absent or atrophic (very small). It is important to determine which of these is true because a testicle left inside the abdomen could form a tumor later in life. Such a tumor may go undetected until it becomes quite large or causes symptoms. Unfortunately, there is no X-ray that can definitively determine whether a testicle is present so this situation always requires surgery. Most surgeons use a technique called laparoscopy. They will find one of three situations: 1) blind ending testicular blood vessels suggesting an absent testicle; 2) vessels exiting the abdomen, proving that there is no testicle within the abdominal cavity; or 3) a testicle in the abdomen. If a testicle is found, it is brought down into the scrotum or removed, depending on its condition and location.
What treatment(s) are available?
Treatment should be given anytime after six months of age. The time between six and 18 months of age is generally considered best, when taking into account surgical, anesthetic and psychological factors. The two treatment options are either hormonal or surgical. In the United States the only option available for hormonal treatment is human chorionic gonadotropin (hCG) (in Europe gonadotropin releasing hormone, GnRH, is also available). HCG injections are given weekly or biweekly, usually over four weeks, in variable doses based on the infant's weight. Although it is safe and very successful in proving that retractile testicles are down in the scrotum, it is only curative in 10 to 15% of truly undescended testicles. Many parents therefore prefer surgical treatment. The operation is called an orchiopexy. It requires general anesthesia, but the baby can almost always go home the same day and usually acts entirely normal within one to two days. An incision about an inch long is made in the groin area (usually it can hardly be seen later). The testicle is separated from all surrounding tissues (and if there is a hernia, this is fixed at the same time) so that it comes easily into the scrotum where it is stitched into place. In some cases, the testicle is too high for this simple operation and more complex procedures (and sometimes even two operations) are needed.
What can be expected after treatment?
After treatment, the testicle usually develops to normal size in the scrotum. However, in some cases the testicle is abnormal to start with and never grows properly. In other cases, even though it is of normal size, sperm never develop. In most cases of an undescended testicle on one side, the chances of ultimately fathering a child are very high — indeed, the same as normal. It is recommended that, as a teenager, these patients have regular physical examinations and be reminded to perform monthly testicular self-examination.