In the fetus, the testes are in the abdomen. As development progresses, they migrate downward through the groin and into the scrotum. This event takes place late in fetal development, during the eighth month of gestation. In some newborn boys the testes are not present in the scrotum, either because the testes did not descend or because the testes never developed in the fetus.
Eighty percent of all undescended testes cases naturally correct themselves during the first year of life. Only 3 to 4 percent of full-term baby boys have undescended testes, and half of those complete the journey by the age of three months. Up to 30 percent of boys born prematurely have testes that have not yet made the full descent. In 5 percent of cases of undescended testes, the testis on one side is completely absent. In 10 percent of cases, both testes are completely absent.
Causes and symptoms
There are many different and complex reasons why one or both testes may not descend. Sometimes the failure is due to problems that occur during pregnancy with the tissues as they are developing or with hormone levels in the developing fetus. If the testes did not descend because they are absent, then the likely cause is different than for testes that are present but did not descend. In the case of absence, it is possible that the testes never developed at all because the blood flow was cut off to them as they were developing, preventing their formation. One or both of the testicles can be undescended; therefore, the scrotum can appear to be either missing or lopsided.
When to call the doctor
The doctor will check for the testes in the scrotum during the normal newborn examination. If the parent notices that their male infant's testes do not appear normal or do not appear to be present at all, the parent should alert the doctor. If the testes have not descended by the time the child is six months of age, the parent should call the doctor to begin discussing possible treatment options.
The newborn examination always checks for testes in the scrotum. It they are not found, a search will be conducted, but not necessarily right away. If the testes are present at all, they can be anywhere within a couple inches of the appropriate spot. In most cases, the testes will drop into place later. In 5 percent of cases, one testis is completely absent. In 10 percent of cases, the condition occurs on both sides. Presence of undescended testes is differentiated from absence of testicles by measuring the amount of gonadotropin hormone in the blood.
Once it is determined that the testes will not naturally descend, treatment options must be considered. Hormone therapy is a possible treatment but does not have a very high success rate. Another treatment option is surgery. The procedure is called an orchidopexy and is relatively simple once the testes are located. The surgery is usually performed when the boy is between one and two years old.
Of full-term baby boys who have undescended testes, half will descend on their own without intervention
Many children who have undescended testes have reduced fertility as adults. It is thought that as many as 50 to 75 percent of children with undescended testes have problems with fertility as adults. Children with undescended testes are also more likely to develop hernias and have problems with their urinary tract.
There is no known way to prevent undescended testes.
Undescended testes are of concern because, although they are not known to be a threat to the child's immediate health, they are associated with an increased likelihood of negative outcomes later in life, including an increased likelihood of sterility and an increased incidence of testicular cancer.
Cryptorchidism—Undescended testes, a condition in which a boy is born with one or both testicles in the lower abdomen rather than the scrotum.
Embryonic—Early stages of life in the uterus.
Fetal—Refers to the fetus. In humans, the fetal period extend from the end of the eight week of pregnancy to birth.
Orchiopexy—A surgical procedure that places an undescended testicle in the scrotum and/or attaches a testicle to the scrotum.
Behrman, Richard E., Robert M. Kliegman, and Hal B. Jenson, eds. Nelson Textbook of Pediatrics. Philadelphia: Saunders, 2004.
Goldman, Lee, and J. Claude Bennett, eds. Cecil Textbook of Medicine. Philadelphia: Saunders, 2004.
Rajfer, Jacob. "Congenital Anomalies of the Testes and Scrotum." In Campbell's Urology, edited by Patrick C. Walsh, et al. Philadelphia: Saunders, 2002.
Rozauski, Thomas, et al. "Surgery of the Scrotum and Testis in Children." In Campbell's Urology, edited Patrick C. Walsh, et al. Philadelphia: Saunders, 2002.
Koo, Harry P. "Is It Really Cryptorchidism?" Contemporary Urology (January 2001): 12.
American Urological Association. 1000 Corporate Blvd., Linthicum, MD 21090. Web site: <www.urologyhealth.org>.
Tish Davidson, A.M.