Testicular descent is the process by which a testicle moves from the abdomen into the scrotum. This movement is necessary for the testicles to function correctly later in life. Monitoring this process is an important part of pediatric care to ensure long-term reproductive health. Failure of one or both testicles to complete this journey is known as cryptorchidism.
The Normal Timeline of Testicular Descent
The descent process begins in utero, with the testicles developing in the abdominal cavity. The majority of descent occurs late in pregnancy, during the third trimester, typically between 25 and 30 weeks of gestation. At the time of a full-term birth, approximately 97% of male infants have both testicles positioned in the scrotum.
For infants born with one or both testicles undescended, spontaneous movement into the scrotum is still possible after birth. This natural correction is most likely to occur within the first three months of life. If a testicle has not descended by six months of age, spontaneous descent is unlikely afterward. This six-month mark is used as a benchmark for determining when medical intervention may be necessary.
Identifying Undescended Testicles
The primary way to confirm descent is through physical examination, routinely performed by pediatric healthcare providers. The defining sign of a true undescended testicle (cryptorchidism) is a scrotum that appears empty or underdeveloped on one or both sides. The testicle may be felt higher up in the groin region, along the natural path of descent.
Parents or caregivers should distinguish between a truly undescended testicle and a retractile testicle. A retractile testicle moves freely between the scrotum and the groin due to the cremasteric reflex, a muscle contraction often triggered by cold or touch.
A retractile testicle can be easily guided by hand into the scrotum and will remain there temporarily. In contrast, a truly undescended testicle is either not palpable or cannot be manipulated down into the scrotum. If a testicle is consistently absent and cannot be gently guided down, a medical evaluation is warranted.
Why Descent Matters and Associated Risks
The biological need for descent relates to temperature regulation. The testicles must be kept cooler than the core body temperature for optimal function, and the scrotum provides this slightly cooler environment. Leaving a testicle in the abdomen or groin, where the temperature is higher, can cause progressive damage to sperm-producing cells.
One long-term risk of untreated cryptorchidism is impaired fertility potential in adulthood. The risk is higher when both testicles fail to descend, but even a single undescended testicle can affect future reproductive capacity.
Another concern is the increased risk of developing testicular germ cell tumors, a form of cancer. Males who had an undescended testicle have a cancer risk several times higher than the general male population.
The risk of malignancy remains elevated even after surgical correction, though timely intervention may reduce the risk magnitude. Undescended testicles are also more susceptible to testicular torsion, a painful condition where the spermatic cord twists and cuts off the blood supply.
Medical Management and Treatment Options
If a testicle has not descended spontaneously by six months of age, a referral to a surgical specialist is recommended. The standard treatment for a confirmed undescended testicle is orchiopexy, a surgical procedure. This operation involves relocating the testicle from the groin or abdomen and permanently fixing it within the scrotum.
The goal of orchiopexy is to place the testicle into its proper position to encourage healthy development and make future examinations easier. Guidelines recommend performing the procedure between six and eighteen months of age. Intervention within this optimal window maximizes the potential for preserving fertility and mitigating the long-term risk of malignancy.