Page last reviewed: 13/07/2011
Undescended testicles are a common childhood condition where a boy is born without having one or both testicles in their scrotum. The medical term for undescended testicles is cryptorchidism.
The scrotum and testicles
The scrotum is a small sac of skin that hangs underneath the penis. It holds the testicles in place.
The testicles are the two oval-shaped male sex organs that sit inside the scrotum on either side of the penis. Testicles are an important part of the male reproductive system as they produce sperm and the hormone testosterone, which plays an important role in male sexual development.
The development of the testicles
During pregnancy, the testicles form inside the baby's abdomen (the area of the body that contains the stomach), before slowly moving down into the scrotum as the baby develops. The testicles are usually in place by the eighth month of pregnancy.
For reasons that are still unclear, one or both testicles sometimes do not move into the scrotum by the time the baby is born.
The need for treatment
Having undescended testicles does not present any immediate health problems, and it is painless. In many cases, the testicle(s) will descend into the scrotum some time during the first four months of the baby's life.
If the testicle(s) do not descend by this time, treatment is usually recommended.
Treatment is usually recommended for three reasons. Boys with undescended testicles:
- may have fertility problems in later life
- have an increased risk of developing testicular cancer
- may have problems with their self-esteem and body image if they are 'missing' one or both of their testicles.
Treatment options include:
- using artificial hormones to stimulate the descent of the testicle(s)
- using a type of surgery, known as an orchidopexy, to move the testicle(s) into the correct position inside the scrotum. This is more common
How common are undescended testicles?
Undescended testicles are one of the most common congenital conditions that affect boys. Congenital means that the condition is present at birth. It is estimated that 3-5% of newborn boys have undescended testicle(s).
In around 80% of cases, only one of the testicles is affected. Most cases will resolve without the need for treatment, although a small number of boys (0.7-1%) have testicles that stay undescended into adulthood unless treated.
The outlook for boys who are born with persistent undescended testicles is usually very good. In most cases, orchidopexy is a relatively straightforward type of surgery that has a good success rate. If the condition is treated at an early age, the boy's fertility should be unaffected.
Boys who are born with undescended testicles have an increased risk of developing testicular cancer later in life, although this risk is very small (an estimated one in 1,000-2,500 chance).
Page last reviewed: 13/07/2011
Undescended testicles are broadly grouped into two categories:
- Palpable undescended testicles: the testicle(s) can be felt during a physical examination.
- Unpalpable undescended testicles: the testicle(s) cannot be felt during a physical examination.
An object is palpable if it can be touched or felt. Unpalpable means that an object cannot be touched or felt.
Palpable undescended testicles
Palpable undescended testicles are the most common type of undescended testicles, and account for 80% of all cases.
In most cases, palpable undescended testicles are located just above the scrotum. They are lodged at the end of the inguinal canal (a channel that runs from the lower abdomen down towards the penis and scrotum).
Unpalpable undescended testicles
There are three main types of unpalpable undescended testicles:
- Abdominal or intra-abdominal, which accounts for around 40% of cases of unpalpable testicles.
- Inguinal, which accounts for around 40% of cases.
- Atrophic or absent, which accounts for about 20% of cases.
The three types of unpalpable undescended testicles are described in more detail below.
Abdominal or intra-abdominal
An abdominal, or intra-abdominal, testicle occurs when the testicle is located inside the abdomen, usually close to the upper opening of the inguinal canal.
An inguinal testicle is a testicle that has moved into the inguinal canal, but has not moved far enough down towards the scrotum to be detected during a physical examination.
Atrophic or absent
An atrophic testicle is a testicle that is abnormally small. An absent testicle is where one testicle has never been created during a baby's development inside the womb.
Both atrophic and absent testicles can have a variety of causes.
Page last reviewed: 13/07/2011
Undescended testicles are caused by something that interrupts the normal development of the testicles.
At an early stage of development, all unborn babies have identical genitals, whether they are male or female.
The development of the genitals into male or female depends on the pair of sex chromosomes that the baby receives from its parents. Sex chromosomes are a pair of deoxyribonucleic acid (DNA) molecules that are either X- or Y-shaped. They play a vital role in the baby's sexual development.
In normal development, once the testicles have formed they stay inside the baby's abdomen until the seventh month of pregnancy. It is then thought that hormones 'activate' the descent of the testicles. They move slowly down from the abdomen, through the inguinal canal and into the scrotum. In most cases, the testicles should be in place shortly before, or soon after, birth.
In males, at around the ninth week of pregnancy, the male sexual chromosomes trigger the production of a hormone called testosterone. Testosterone triggers the development of the male genitals. At this stage, problems relating to absent, or atrophic, testicles can arise. For example, the penis may develop normally but, for unknown reasons, the testicles do not.
Alternatively, abnormal genital development may happen due to a rare condition, such as androgen insensitivity syndrome. This is where the body is partially insensitive to hormones, such as testosterone, which results in the baby being born with ambiguous genitalia (the genitals have male and female characteristics).
In most cases of undescended testicles, something seems to interrupt the descent of one or both testicles, and it (or they) remain inside the abdomen or the inguinal canal.
It is not known exactly why this happens, although a number of risk factors have been identified.
The known risk factors for undescended testicles are as described below.
- Low birth weight: boys with a birth weight of less than 2.5 kg (5.5lb) are two to three times more likely to be born with undescended testicles than the population at large.
- Being born prematurely: the earlier a boy is born, the more likely he will be born with undescended testicles.
- Having a family history of undescended testicles: having an older brother with undescended testicles means that a boy is three times more likely to be born with the condition compared with the general population.
- Maternal diabetes: women who have type 1 and type 2 diabetes are twice as likely to give birth to a boy with undescended testicles compared with women who do not have diabetes.
- Smoking by the mother during pregnancy.
- Alcohol consumption by the mother during pregnancy (see below).
The Department of Health (DH) recommends that women avoid drinking any alcohol while pregnant. If you choose to drink alcohol while you are pregnant, do not drink more than 1-2 standard drinks of alcohol, once or twice a week. Also avoid binge drinking and getting drunk.
Testicular dysgenesis syndrome
Over the last 30 years, there has been a marked increase in the number of cases of undescended testicles in Western countries. Rates of three other conditions that affect the male genitals have also increased. These are:
- a low sperm count
- testicular cancer
- hypospadias - a condition where the urethra (the tube in the penis through which urine passes) is not in the correct position
Some researchers believe that all these conditions, along with undescended testicles, are interrelated. Rather than being separate conditions, they are different forms of a single underlying syndrome that is known as 'testicular dysgenesis syndrome (TDS)'.
If TDS exists, it may be caused by exposure to chemicals during pregnancy that disrupt the normal balance of hormones. This may interfere with the normal development of the male genitals.
Chemicals that are known to disrupt hormonal balance are called endocrine disruptors.
Examples of endocrine disruptors include:
- some types of pesticide
- polychlorinated biphenyls (PCBs) - a chemical compound that is used as a coolant
- dibutyl phthalate - a chemical that is used to manufacture cosmetics, such as nail polish
In most countries, including the Ireland, many endocrine disruptors such as PCBs have been withdrawn due to a link with health problems. But there are still concerns that people may still be exposed to endocrine disruptors through contamination of the food chain.
The World Health Organisation (WHO) has done extensive research to find out whether exposure to endocrine disruptors is causing the rise in conditions that affect male fertility.
Researchers have concluded that direct exposure to high levels of endocrine disruptors can negatively affect human health and male fertility.
But there is not yet enough evidence to prove a definite link between health problems and indirect exposure to low levels of endocrine disruptors. Indirect exposure is the type of exposure that occurs if the food chain is contaminated.
Page last reviewed: 13/07/2011
The first stage in diagnosing undescended testicles is to carry out a physical examination to see whether the testicles can be felt near the scrotum (whether they are palpable).
This is usually done by placing your baby in a warm bath. This helps them to relax, and it expands the skin around the scrotum, which makes it easier to physically examine them.
If the examination reveals that both testicles are undescended and unpalpable (cannot be felt), a number of blood tests can be used to check whether hormonal problems may have disrupted the testicles' normal development.
A procedure called a diagnostic laparoscopy is usually needed to find an unpalpable testicle. Diagnostic laparoscopy is a type of 'keyhole surgery' that uses an instrument called a laparoscope.
A laparoscope is a small, flexible tube that contains a light source and a camera. The camera relays images of the inside the abdomen, or pelvis, to a television monitor.
Depending on where the testicle is located, it may be possible to perform surgery immediately in order to reposition the testicle into the scrotum.
Page last reviewed: 13/07/2011
For most cases of undescended testicle(s), surgery to reposition the testicle(s) into the scrotum is usually recommended. This type of surgery is known as an orchidopexy.
Exactly when the operation is carried out will depend on your child's health. Ideally, surgery should be performed between six months and two years of age. This is because waiting longer than two years has been shown to increase a boy's risk of developing fertility problems and/or testicular cancer.
Increasingly, orchidopexies are performed using laparoscopic (keyhole) surgery. This type of surgery causes less post-operative pain, and has a faster recovery time than open surgery.
During the procedure, the surgeon makes a small incision (cut) in your child's abdomen, before passing small surgical instruments through the incision in order to free the testicle from the surrounding tissue.
The testicle is then moved down the inguinal canal, and repositioned in the scrotum using a second incision. The inguinal canal is then usually sealed to prevent the testicle from moving back out of the scrotum.
An orchidopexy is performed under a general anaesthetic,which means that your baby will not feel any pain during the operation. In most cases, surgery can be performed as day surgery, so your child will be able to return home on the same day.
Your child may feel sick for the first 24 hours after surgery. Feelings of nausea are a common side effect of general anaesthetic. They are nothing to worry about.
The following advice should help to speed up your child's recovery time and reduce their risk of post-operative complications.
- Your child will need to have regular pain relief for three days after the operation. Activities such as playing games, watching television and reading together may help to keep his mind off the pain.
- Encourage (but not force) your child to drink plenty of fluids.
- Your child's groin area may feel sore for a while after the operation. Wearing loose-fitting clothing will help.
- Keep the operation site clean and dry, and avoid soaking the area during a shower or bath.
- Your child should not ride a bicycle or use 'sit-on' toys, for one month after the operation. This is to prevent the testicles travelling back up into the abdomen.
Be alert for any signs that the site of the surgery has become infected. These include:
- your child being in a lot of pain, and the prescribed pain relief not working
- your child having a high temperature (fever) of 38ºC (100.4ºF) or above
- the site of the surgery being red, inflamed and/or feeling hotter than the surrounding area
- a discharge of fluid, or pus, from the site of the surgery
If you notice any of these signs and symptoms, contact your GP as soon as possible for advice.
Results of surgery
As a general rule, the closer the testicle is to the scrotum, the more likely surgery will be successful.
The success rates for treating palpable testicles that are located near the scrotum are estimated to be between 80-90%.
The success rates for treating unpalpable testicles is between 75-90%, depending on where the testicle is located. If surgery fails, further surgery may be needed to reposition the testicle in the scrotum.
Alternatives to surgery
An alternative to surgery is to use synthetic hormones that encourage the testicle move out of the abdomen and down into the scrotum.
Hormone therapy is usually only recommended if your child's testicle(s) are close to the scrotum. This is because the treatment is usually ineffective in treating unpalpable testicles that are located in the inguinal canal or abdomen.
Hormone therapy may also be recommended if both testicles are undescended and blood tests have shown that this is due to underlying problems with their hormones.
Page last reviewed: 13/07/2011
As with any type of surgery, an orchidopexy carries the risk of causing complications.
The most serious complication of surgery is testicular atrophy. The blood supply cannot sustain the testicle in its new position, which causes the testicle to wither away. This is known as testicular atrophy, and it occurs in an estimated 5% of cases.
If testicular atrophy occurs, your child's fertility should be unaffected as long as he still has one healthy testicle.
Cosmetic surgery can be performed to remove the affected testicle and place an artificial implant in your child's scrotum.
Damage of the vas deferens
Another possible complication of an orchidopexy is that the vas deferens may be accidentally damaged.
The vas deferens is a tube that connects the testicle to the urethra. The urethra is the tube through which the sperm passes when a man ejaculates. Damage to the vas deferens occurs in an estimated 1% of cases.
If the vas deferens is damaged during surgery, further surgery is usually needed to repair it. If left untreated, it can cause fertility problems in later life.