What are undescended testes?
Cryptorchidism means ‘hidden testis’ and is a condition where one or both testes (testicles) are not in their normal position in the lower part of the scrotum. It’s commonly called ‘undescended testes’.
During development before birth, the testes begin developing inside the abdomen and gradually move down into the scrotum. The descent of the testes is completed after birth. If this process doesn’t occur normally, the testes may be located inside the abdomen, in the groin, above the scrotum or high in the scrotum.
Undescended testes occur in around 1 in 100 to 1 in 20 newborn babies born at full term. In preterm babies, undescended testes can occur in up to half of all newborns1.
Undescended testes may not always be diagnosed at birth because the descent of the testes may appear normal at birth but then doesn’t continue normally. About 1 in 100 to 1 in 50 boys older than one year are diagnosed with undescended testes each year1.
Symptoms of undescended testes
The only sign of undescended testes is when you can’t see or feel one (or both) testis in the scrotum. This can be noticed at birth, or later. Cryptorchidism does not cause pain or any other symptoms.
Causes of undescended testes
The cause of undescended testes is unknown. There may be a number of reasons why one or both testes fail to descend during development2.
There are many genetic and hormonal factors that can influence the development of the testes3.
Diagnosis of undescended testes
A doctor can diagnose undescended testes by performing an examination. Medical imaging or exploratory surgery are rarely required to diagnose undescended testes.
Treatment of undescended testes
If you have undescended testes, you’ll need to have surgery. This is usually an operation called orchidopexy, in which the testis (testicle) is moved into the scrotum and secured in place . In some cases, an undescended testis may not have formed properly and may need to be removed4.
Surgery for babies born with cryptorchidism is usually performed around six months of age4.
Health effects of undescended testes
In order to function properly, the testes need to be kept slightly cooler than your core body temperature. This is why they’re located in the scrotum, outside the abdomen. If the testes aren’t located inside the scrotum, this can cause problems with their function.
Undescended testes seem to result in smaller testis size, and testosterone production in adulthood may be lower than normal3.
What to do about undescended testes
If you can’t see or feel one or both testes in the scrotum, you should see your doctor about it. Surgery may be necessary to reposition the testis to minimise the negative effects on its function. The sooner the problem is fixed, the better the outcome.
Questions to ask your doctor about undescended testes
● What should I look out for after my surgery to correct cryptorchidism?
● How is surgery performed to fix cryptorchidism?
● Could there be any other abnormalities in my development that should be looked into?
 Sijstermans et al., 2007. The frequency of undescended testis from birth to adulthood: a review. International Journal of Andrology
 Sarila et al., 2021. Testicular descent: A review of a complex, multistaged process to identify potential hidden causes of UDT. Journal of Pediatric Surgery
 Rodprasert et al., 2020. Hypogonadism and cryptorchidism. Frontiers in Endocrinology
 Rabinowitz & Cubillos, 2020. Cryptorchidism. https://www.msdmanuals.com/en-au/professional/pediatrics/congenital-renal-and-genitourinary-anomalies/cryptorchidism
Undescended testes fact sheet