Written by Ada’s Medical Knowledge Team
What is cryptorchidism?
Cryptorchidism is also known as undescended testicles (UDT), or undescended testes, and is usually medically defined as a condition in which a testis is not in the scrotum and doesn’t descend into the scrotum by the time the baby is four months old. 1 It is the most common congenital abnormality of the male genitalia 2 and affects about three in every ten male infants born prematurely. 3 Between one and six percent of all male babies are affected. Usually, the condition is unilateral, affecting only one testis. Rarely, the disorder is bilateral, affecting both testes. ref1 4 Most cases are idiopathic, which means that the cause is unknown. 5
Cryptorchidism is not painful for the infant, and in eight out of ten cases it resolves without medical intervention. Most cases of cryptorchidism are diagnosed during the routine checks that the baby undergoes at birth. The others are usually diagnosed during infancy, childhood or early adolescence. 4
If you think that you or a loved one may be experiencing symptoms of chryptorchidism, get an assessment with the free Ada app.
The development of the testicles
The testicles develop in two main phases while in utero. The first phase, which is controlled by male hormones known as androgens, occurs between the eighth and 15th weeks of gestation. 6 During this phase, the testicles develop, but are held in the fetus’s abdominal cavity by a ligament that allows very little movement. 4 ref6 It is relatively rare for complications to happen during this phase.
The second phase takes place between 25 and 35 weeks of gestation, when the testicles begin to migrate towards the scrotum. 7 Most cases of cryptorchidism develop in this phase. 6 However, in the vast majority of infant males, both testicles are present in the scrotal sac at birth.
In approximately 80 percent of cases of cryptorchidism, one or both scrotal sacs are empty at birth. 4 In most cases where the testes have not descended by the time the baby is born, they will have descended by the age of three months, due a postnatal surge in testosterone levels. However, if they have not done so by the time the baby is six months old, it is unlikely that they will do so on their own. 1
There are various forms of cryptorchidism:
- Arrested testicle: one or both testes stay in the inguinal canal (85% of cases), abdomen, or retroperineum. 8
- Ectopic testicle: in which one or both testes descend normally but are diverted to an aberrant position.
- Absent testicle: in which the testis does not develop.
- Ascending testicle: in which the testes are originally in a normal scrotal position, and then “ascend” and become undescended. This can require surgery to correct.
There is also a special form, known as retractile testes, in which the testes are pulled up out of the scrotum. They can usually be manipulated back into the scrotum. Retractile testes are quite common and no reason for concern.
In some cases, what appears to be an undescended testicle may in fact be a retractile or ascended testicle. These tend to be more common in older children than they are in infants.
A retractile testis occurs when the cremasteric reflex is oversensitive, and generally does not need treatment as the testis is otherwise present and descended. A retracted testis can usually be manipulated back into the scrotum and remain there without being held in place. The condition is usually resolved completely by the time puberty begins. 9 Boys with this condition need to be monitored for ascending testes, but there is usually no cause for concern.
In cases where the testicles do not descend into the scrotum of their own accord, medical intervention is necessary to ensure that they do so. Testicles that are not present in the scrotal sac suffer heat stress and may be at higher risk of infertility and developing cancer. 1 10
Causes of cryptorchidism
Most cases of cryptorchidism have no obvious cause.
Risk factors for cryptorchidism
- Premature birth
- Low birth weight
- A family history of undescended testicles, particularly in a father or brother
- Maternal exposure to chemicals, such as diethystilbestrol, pesticides, brominated flame retardants, phthalates, and dioxins, polyvinyl chloride, polychlorinated biphenyls (PCBs), or bisphenol A (BPA)
- Existing congenital malformations of the urinary system or abdominal wall, such as bladder exstrophy 12, prune-belly syndrome, 13 gastroschisis, 14 or hypospadias
- Hereditary syndromes affecting the hypothalamus, connective tissues or nervous system
- Consanguinity of parents
As cryptorchidism is largely asymptomatic, most cases are discovered by caregivers or physicians doing routine physical examinations. If the infant is warm and relaxed, but the testes are not present in the scrotum, they may have undescended testicles. 11 In some cases, especially if the infant is cold, surprised or upset, the cremasteric reflex 15 may cause the testicles to retract out of the scrotum into the body. If this happens, the examination will have to be repeated when the infant is warm and calm.
The majority, around 80 percent, of undescended testicles are palpable (can be felt) during physical examination, due to their location in the neck of the scrotum. If they are in the abdomen or inguinal canal, they may be non-palpable. In such cases, a laparoscopic examination may be necessary to locate them. A laparoscopic exam involves inserting a laparoscope, a thin and flexible device with a camera, into the inguinal canal or abdomen.
In some cases, if the cryptorchidism affects both testicles (bilateral) and the testes are non-palpable, the infant may need to be assessed for a possible disorder or sexual differentiation. In such rare cases, ultrasound or magnetic resonance imaging (MRI) may be used to locate the undescended testicles, especially if they are in the abdomen. 4 In rare cases, only one testicle may be present. This is known as monorchidism. Complete absence of testicles, known as anorchia, is extremely uncommon. 1
Ideally, undescended testes should be located and treatment begun before the infant reaches one year of age. 1 Early treatment gives the testicle the best chance of developing normally, maintaining fertility and minimizing the risk of testicular cancer. 4
Undescended testicles must be treated if they have not descended spontaneously by the time the child is six months of age. After that age, they are unlikely to descend on their own. The goal of treatment for undescended testicles is to move viable undescended testes to the correct position in the scrotum and to remove nonviable testicular tissue if it is present.
The usual course of treatment is almost always surgery, known as orchidopexy, although in some cases, hormonal treatment may be possible.
In cases where the testicle is palpable, the testis can be repositioned using a procedure known as an orchidopexy. The testicle needs to be palpable for this surgery to be an option.
In an orchidopexy, which is usually performed between the ages of six months and 11 years of age, the undescended testicle is brought into the scrotum, along with the vas deferens, 16 testicular blood vessels and spermatic cord. It is then fixed in the scrotum with sutures. 4 This procedure can be done laparoscopically or by open surgery. It is usually done through an incision in the inguinal area,the groin. ref1
If the undescended testis is not palpable, exploratory surgery is performed to determine whether the testis is present at all and then, if it is, whether it is viable. This exploratory surgery can be open surgery or laparoscopic surgery. 17
If the testis is present and viable, a laparoscopic orchidopexy can be performed. In this case, a laparoscope — a small, slender instrument equipped with a light and a camera — will be used to locate the testis and then guide the procedure to bring it into position. Open surgery is not usually performed in cases where the exact location of the testis is unknown. 1If the testicle is high in the abdomen, complications may occur because the blood vessels and spermatic cord may not be long enough to allow movement into the scrotum. 17 If it is discovered that no testes are present, or that only one is present, any atrophied testicular tissue that is found will be removed.
Orchidopexies should be performed as early as possible to maximize fertility potential in later life and keep the risk of testicular cancer to a minimum. Also, they are easier to do if the child is still physically small, as the distances that the vessels and organs need to be moved are shorter. 4
Surgery in the form of orchidopexy is considered the best and most effective treatment for undescended testicles. There is usually no likelihood of long-term problems following such a procedure. 11
Hormonal therapy for undescended testicles is controversial and not widely recommended. It is not generally believed to be very effective, only working in about a fifth of cases. 2
Complications of cryptorchidism
It is generally considered best to correct cryptorchidism when the affected infant is young. If left uncorrected, cryptorchidism can lead to a higher risk of testicular cancer and can affect fertility. There is also a risk of testicular torsion, testicular trauma and inguinal hernia.
Testicular cancer is the most common cancer in men between the ages of 15 and 35 years. 18. Globally, the incidence of testicular cancer appears to be rising, but it has good recovery rates.
Approximately 11 percent of all cases of testicular cancer affect men with a history of undescended testicles. Orchidopexy performed as early as possible in life decreases the risk of testicular cancer developing in the affected testis or testes. 2 If undescended testes are discovered in the inguinal ring or in the abdomen only after puberty, they may have to be removed in order to minimize the risk of testicular cancer.
One of the major risks accompanying untreated undescended testicles is that testicular cancer may not be detected until it is quite advanced, due to the difficulty of self-examining a testicle if it is not palpable. 11 (For more information on how to check for testicular cancer, see FAQs)
If you or someone you love is experiencing symptoms about which you are they are concerned, you can do a free symptom assessment using the Ada app at any time.
Men with a history of cryptorchidism may have lower sperm counts, sperm of poorer quality and lower fertility than men with normally-descended testes. The degree to which men are affected, depends on whether one or both testes were undescended and how long they were undescended before being corrected.
While men with unilateral corrected undescended testicles are generally less fertile than men with bilateral normally-descended testes, they have the same rate of paternity, which means that they are equally likely to father children. However, men with a history of bilateral corrected undescended testes have lower fertility and paternity rates than their counterparts with unilateral undescended or bilaterally descended testicles. Men with uncorrected unilateral or bilateral undescended testes are highest at risk of being infertile.
Treating the undescended testis at an early age is intended to avoid the risk of low fertility by ensuring that the testis is moved to its optimal environment as early as possible. Testes that remain inside the body are at risk of heat stress, which negatively affects the development of sperm and may cause low sperm count, low sperm quality or low semen quality.
Testicular torsion can occur at any age and is about ten times more common among males with cryptorchidism than it is among those with normally-descended testes. It can occur alongside a testicular tumor, because the weight and size of the tumor can distort the testicle and twist it out of place. It is possible that the greater severity of testicular torsion among undescended testicles results from the fact that detection is often delayed due to the testicle’s location inside the body. 19
Symptoms of testicular torsion differ according to the location of the undescended testis, but can include:
- Swelling in the groin (inguinal area)
- Empty scrotal sac on the same side as the swelling
- Acute abdomen, a condition of severe abdominal pain.
Acute abdomen is a medical emergency and medical help must be sought immediately.
If you or someone you care for is experiencing these or any other troubling symptoms, you can start a free symptom assessment at any time using the Ada app.
If the testis is in the inguinal canal, it is at risk of blunt trauma if the affected person receives a blow in that area. The testis may be compressed against the pubic bone and be injured. 19
During the development of the fetus in the womb, the lining of the abdominal cavity extends into the groin. In male fetuses, the testicles and spermatic cords descend through the abdominal lining via a hernia into the inguinal canal and then into the scrotum, after which the abdominal lining closes. In some cases, such as some cases of cryptorchidism, the abdominal lining and hernia do not close properly, and part of the small intestine may move into the inguinal canal. This is usually presents with swelling and pain. The condition requires surgical treatment. 20 21 22
Q: Will I be able to have children if I have a corrected undescended testicle?
A: Yes. If you received treatment early in life, you will have a similar paternity rate as men who had normally-descended testicles.
Q: Does having an undescended testicle affect my testosterone levels?
A: Yes. It may lead to your testosterone levels being lower than the norm. When this is caused by undescended testicles, it is known as primary hypogonadism. However, if your undescended testis was corrected early in life, your testosterone levels may be normal. 23
Low testosterone can also be caused by injury to the testicle, diabetes, medication, aging or even pituitary tumors.
Q: How do I check for testicular cancer?**
A: The most common first symptom of testicular cancer is a painless lump on or inside a testicle. Men should routinely check their testicles for lumps, which can be done by rolling their testicles gently between their fingers and noting any changes. If a lump is found, or there is pain that is not the result of applying too much pressure, men should seek medical help. You can share your symptoms with Ada and get a symptom assessment at any time using the free Ada app.