Undescended Testicle in Babies (Cryptorchidism): Screening and Surgery

At your baby boy's first check-up, the midwife or paediatrician feels his scrotum. Sometimes the sentence comes: "one testicle is missing". An undescended testicle, which doctors call cryptorchidism, is the most common birth anomaly in boys. It often sorts itself out and is very treatable when it does not, but it must not be forgotten.

Here is what you need to know to follow the right timetable: when to wait, when to see a doctor, and why surgery is done early.

What is an undescended testicle?

It is a testicle that has not finished its journey down into the scrotum. During pregnancy the testicles form inside the baby's abdomen, then travel down to the scrotum before birth. When that journey stops along the way, the testicle stays in the abdomen or in the groin. If it has strayed off the normal path, it is called testicular ectopia.

How many babies are affected? About 3 to 4% of newborns, according to the French Association of Urology (AFU), and up to a third of premature babies. The UK's NHS also lists low birth weight and a family history among the risk factors. If your baby was born early, also read our article on the premature baby.

Most of the time the cause is unknown, and nothing you did during pregnancy is responsible.

How is it detected?

By a simple examination of the scrotum, first at the maternity ward, then at every visit to the paediatrician. It is one of the steps of the newborn examination, along with those described in our article on your baby's first checks.

The doctor wants to know whether the testicle is:

• in the scrotum: all is well;
• palpable but too high, in the groin;
• not palpable: it may be in the abdomen, or absent.

An ultrasound is not useful for deciding, La Revue du Praticien points out in 2025: what counts is the clinical examination by a specialist. When both testicles are missing, a hormone work-up is requested.

In Morocco, this check sometimes takes second place between vaccines and weigh-ins. If nobody has mentioned the testicles during the first visits, simply ask the paediatrician to check. Our article on choosing a paediatrician can help you find regular follow-up.

Retractile testicle or undescended testicle: what is the difference?

A retractile testicle (also called a "yo-yo" or ascending testicle) has come down properly, but a small muscle pulls it up towards the groin when the child is cold, frightened or touched. The doctor can gently guide it back into the scrotum, where it stays. An undescended testicle, on the other hand, does not come down, or goes straight back up.

A retractile testicle should not be ignored, though. The AFU indicates that most settle with age, but that about 30% do not correct themselves and have to be fixed surgically. Hence the yearly check-up, at least until puberty.

At what age should the operation be done?

Early. The recommendations have changed: the AFU used to aim for surgery before the age of 2. Today La Revue du Praticien advises referring the child to a paediatric surgeon or urologist at around 6 months if the testicle has not come down, and as soon as it is diagnosed if it is discovered later. The NHS places surgery at around one year. An Australian study published in 2018 in The Lancet Child & Adolescent Health reinforced the idea of operating before 18 months.

Why not wait? Because after one year the testicle rarely comes down on its own. And because a testicle that stays too warm, in the abdomen or groin, develops less well.

In reality, many children are operated on later. A Cameroonian study published in 2024 reports an average age of 6.7 years at the time of treatment, and cites a Moroccan series in which it was 2.6 years. The authors point to lack of information, cost and beliefs. An older boy can perfectly well be operated on; it is simply better not to delay.

In Morocco, the issue is sometimes discovered at the circumcision consultation. The two procedures can then be discussed together with the surgeon (see our article on circumcision in children).

Why does the operation matter?

For two reasons, detailed by the AFU and La Revue du Praticien:

1. Future fertility. A badly placed testicle risks shrinking. The risk of reduced fertility is higher when both testicles are affected.
2. Monitoring. The risk of testicular tumour is higher in these boys, even after the operation. A testicle that has been brought down into the scrotum can be felt and monitored; one hidden in the abdomen cannot.

Hormone treatments, offered for a long time, are no longer recommended.

How does orchidopexy go?

The surgeon frees the testicle, brings it down into the scrotum and fixes it there. The operation is done under general anaesthesia, through a small incision in the groin, or by keyhole surgery (laparoscopy) if the testicle is in the abdomen. Sometimes two operations a few months apart are needed.

The AFU describes an operation that is not very painful in the usual forms, with a stay of one to two days in hospital or day surgery. Afterwards:

• a painkiller prescribed by the doctor, at the dose he or she sets;
• a scrotum that is sometimes swollen or hard for a few days (a small harmless bruise);
• no bike, scooter or swimming pool for about two weeks;
• a follow-up with the surgeon in the following months.

And hydrocele, is it the same thing?

No. A hydrocele is a scrotum swollen by fluid around a testicle that has come down properly. It affects at least 5% of newborns according to the Mayo Clinic, a little more often premature babies. Soft and painless, it often disappears on its own before the age of one.

Have it checked if it persists after one year, grows, or changes size during the day: this may signal a connection with the abdomen, linked to an inguinal hernia. To follow your child's growth more generally, our guide to the growth chart is a good reference.