Also known as cryptorchidism, undescended testes is a congenital condition
characterized by testicles that do not follow the normal developmental
pattern of moving into the scrotum before birth.
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.
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
An orchiopexy is used to repair an undescended testicle in
childhood. An incision is made into the abdomen, the site of the
undescended testicle, and another is made in the scrotum (A). The
testis is detached from surrounding tissues (B) and pulled out of
the abdominal incision attached to the spermatic cord (C). The
testis is then pulled down into the scrotum (D) and stitched into
(Illustration by Argosy, Inc.)
by the age of three months. Eighty percent of all undescended testes
cases naturally correct themselves during the first year of life. Of those
cases that do not correct themselves naturally, intervention is very
important, because undescended testes increase the likelihood of sterility
. Undescended testes are twice as likely to develop cancer as normally
descended testes. Ten percent of all testicular cancers are in undescended
testes. An adult man is three to 17 times more likely to develop
testicular cancer if he has had a testis
that did not descend naturally. Surgery done to move the testis into the
scrotum does not reduce the likelihood of malignancy but allows
accessibility of the testes to screen for masses which will allow early
treatment. The incidence of testicular cancer in men who did not have both
testes descend normally is about 1 in 2000.
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, a condition in which a boy is born with one
or both testicles in the lower abdomen rather than the scrotum.
—Early stages of life in the uterus.
—Refers to the fetus. In humans, the fetal period extend from the
end of the eight week of pregnancy to birth.
—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
, edited by Patrick C. Walsh, et al. Philadelphia: Saunders, 2002.
Rozauski, Thomas, et al. "Surgery of the Scrotum and Testis in
, edited Patrick C. Walsh, et al. Philadelphia: Saunders, 2002.
Koo, Harry P. "Is It Really Cryptorchidism?"
(January 2001): 12.
American Urological Association.
1000 Corporate Blvd., Linthicum, MD 21090. Web site: