An undescended testis is more common in boys who are born prematurely. Although in the majority of cases the testis descends by the age of six months, some boys will need an operation, an orchidopexy, to bring the testis down from the abdomen into the scrotum. There is an increased risk of infertility and also cancer if the testis remains in the abdomen.
What is an undescended testis?
In boys, the testes (testicles) begin their development in the abdomen (tummy). Whilst the baby is growing and developing in his mother's womb, the testes gradually travel down into the scrotum (testes' sack). This usually happens towards the end of the pregnancy. At birth, most boys have two testes in the scrotum. However, in some babies, one or both of the testes cannot be felt in the scrotum. The testis will then be undescended. This is also known as cryptorchidism. The testis is usually stuck in the canal that leads from the abdomen to the scrotum (the inguinal canal) but sometimes it stays inside the abdomen.
Usually only one of the testes is affected, but on rare occasions, both testes fail to travel to the scrotum.
An undescended testis is more common in premature babies, affecting around one in four premature babies. Around 1 in 20 male babies born at term (born at the normal time) are born with an undescended testis. Many of these will become descended in time. However, for around 1 in 70 cases, the testis remains undescended after the child is 1 year old.
Very rarely, there may be an absent testis which has not developed at all.
Can the testis still descend after birth?
In some cases, the testis that is undescended will still descend after birth. However, this is less likely the older the baby becomes. Both testes should be in the scrotum by the time your child is 1 year old.
How is an undescended testis diagnosed?
This is usually found when the baby is examined, either shortly after birth or during the six- or eight-week baby check. This is found by examining the baby's scrotum gently to feel for the presence (or absence) of the testes.
In some children, the testes may have descended to the scrotum but are not always able to be felt there. This is because the testes can sometimes rise back into the body, especially when the baby is cold. If you can feel both testes in the scrotum at other times - for example, when your baby is having a bath - then your baby does not have undescended testes and does not need any treatment.
What symptoms does an undescended testis cause?
Having an undescended testis does not cause any symptoms at all. It does not cause pain.
What is the problem with an undescended testis?
If one or both testes are left in the abdomen then they do not mature properly. The amount of sperm and fertility levels are lower in men who have had an undescended testis, especially if it was not treated early in childhood. This is because the testes need to be a few degrees cooler than the rest of the body in order to produce sperm.
It is also impossible for men with an undescended testis to check for testicular cancer, as an undescended testis cannot be felt in the abdomen. There is a large increased risk of testicular cancer in men who have not had their undescended testis surgically fixed. There is still some increased risk in men who had an undescended testis fixed when they were a baby.
What is the treatment for an undescended testis?
If the child is under six months old when an undescended testis is diagnosed, then some time is usually given to see if it will descend on its own. The majority will descend on their own and do not need treatment. However, babies over the age of 6 months, with an undescended testis, are usually referred to a specialist for treatment.
An undescended testis is best treated in early childhood. Most can be felt in the inguinal canal and are usually treated by a short operation called an orchidopexy.
This is an operation to bring the testis down from the abdomen to its usual place in the scrotum. This is a short operation which is done under a general anaesthetic. It is usually possible for your child to go home on the same day of having the operation.
The orchidopexy can either be carried out using traditional open surgery or by keyhole surgery. The surgeon will move the testis down into the scrotum and then close up the passage through which the testis should have travelled, to stop the testis moving back into your child's abdomen.
There are usually no long-term problems following an orchidopexy for an undescended testis. However, boys who have had an undescended testis in the past should be very vigilant about self-examination for testicular cancer when they are older.
Occasionally, men need treatment for an undescended testis. The testis can either be removed or orchidopexy can be performed. The type of operation will depend on the age of the man, the site of the testis and whether there is a normal testis on the other side.
Dr Tim Kenny
Dr Laurence Knott
Prof Cathy Jackson