Undescended testes are one of the conditions looked for specifically in the newborn examination (NIPE) that happens in the first 72 hours of life and again at 6 to 8 weeks. Finding that a testis has not descended into the scrotum is common enough that it forms a routine part of the newborn check, and most parents will be told clearly what will happen next.
Understanding the condition, the distinction between truly undescended and retractile testes, and why the timing of treatment matters helps parents make sense of what can feel like an alarming finding in a newborn.
Healthbooq (healthbooq.com) covers newborn health and development, including conditions identified at newborn examination and guidance on what to expect at each stage of assessment and management.
How Testes Develop and Descend
During fetal development, the testes form inside the abdomen near the kidneys and descend through the inguinal canal into the scrotum in the final weeks of pregnancy. In premature babies, this process may not yet be complete at birth: around 30 per cent of boys born at 30 weeks or earlier have undescended testes, compared to around 2 to 5 per cent of term babies.
After birth, descent can continue spontaneously under the influence of the postnatal testosterone surge that happens in the first three months of life. For this reason, re-examination at 6 to 8 weeks is standard practice, and many testes that were undescended at birth have descended by this point.
If a testis has not descended by around three months, spontaneous descent becomes unlikely. The 6 to 9 month review checks for this. If an undescended testis is confirmed at that stage, referral for surgical assessment is appropriate.
Retractile Versus Truly Undescended
The retractile testis is a source of considerable parental anxiety and some clinical confusion. A retractile testis has descended normally into the scrotum but is drawn up into the groin by the cremasteric reflex (a muscle reflex that pulls the testis upward in response to cold, touch, or anxiety). It can often be gently manipulated back into the scrotum, where it will sit without tension before retracting again.
Retractile testes are not a concern in the great majority of cases. They tend to become permanently scrotal at puberty as the testis grows larger and the cremasteric reflex weakens. They do not carry the same risks as truly undescended testes.
The distinction from a truly undescended testis is made on examination. A testis that cannot be brought into the scrotum at all, even with gentle manipulation, is genuinely undescended. A testis that can be brought down but immediately springs back to the groin is retractile.
Why Undescended Testes Need Treatment
There are two main reasons.
Fertility: the testis requires a temperature slightly below body temperature for normal sperm production. Inside the abdomen or inguinal canal, the temperature is too high. Prolonged cryptorchidism reduces sperm production capacity. Early orchidopexy (surgical fixation of the testis in the scrotum) before 18 months of age preserves more fertility potential than later treatment.
Risk of malignancy: undescended testes have an increased risk of testicular cancer in adult life, roughly three to five times higher than the general male population. This risk is reduced but not entirely eliminated by orchidopexy. Men with a history of undescended testes are advised to be familiar with testicular self-examination.
Earlier treatment (before 12 to 18 months) appears to produce better outcomes for both fertility and cancer risk than treatment at two or three years or later. This is why NICE and the British Association of Paediatric Urologists recommend orchidopexy at 6 to 18 months.
The Procedure
Orchidopexy is performed under general anaesthetic as a day case. The operation takes around 30 to 45 minutes. The testis is located (either in the inguinal canal or occasionally in the abdomen), brought down, and fixed in the scrotum with dissolvable sutures. Recovery is generally quick, with most boys back to normal activity within a week.
If the testis is in the abdomen and cannot be brought down in one operation, a two-stage laparoscopic procedure may be needed.
Rarely, the testis is absent (vanishing testis syndrome), which occurs when the testis loses its blood supply in fetal development. If this is found at surgery, no further intervention is usually needed, though a prosthesis can be placed at a later age if desired.
What Parents Can Do
Parents of baby boys should be aware of whether both testes were found to be in the scrotum at the newborn check and at the 6 to 8 week check. If there is any uncertainty, asking the midwife or GP directly is appropriate.
If a testis is found not to have descended by six months, the referral pathway should be in motion. If the 6 to 9 month review happens and an undescended testis has not been referred, parents can ask for this to happen.
From adolescence onward, men with a history of cryptorchidism (even after treatment) should be advised to perform regular testicular self-examination and to report any unusual lumps promptly.
Key Takeaways
Undescended testes (cryptorchidism) is the most common genital abnormality in male infants, present in around 2 to 5 per cent of term baby boys and more commonly in premature babies. The majority of undescended testes descend spontaneously in the first three months of life, and the condition is reassessed at the 6 to 8 week check and again at the 6 to 9 month review. Where descent does not occur spontaneously, surgical treatment (orchidopexy) is recommended before 18 months of age to optimise fertility and reduce the risk of malignancy. Retractile testes, which move in and out of the scrotum in response to temperature and muscle contraction, are a different and benign condition that rarely requires treatment.
