A testicle that doesn't move down into its proper place in the scrotum before birth is called an undescended testicle. It's also known as cryptorchidism (krip-TOR-kih-diz-um). Most often, it's just one testicle that doesn't descend into the scrotum, which is the bag of skin that hangs below the penis. But sometimes both testicles are affected.
An undescended testicle is more common in premature babies than it is in full-term infants. An undescended testicle often moves down on its own within a few months after the baby is born. If your baby has an undescended testicle that doesn't correct itself, surgery can be done to move the testicle into the scrotum.
Not seeing or feeling a testicle in the scrotum is the main symptom of an undescended testicle.
Testicles form in an unborn baby's lower belly. During the last few months of pregnancy, the testicles typically move down from the stomach area. They move through a tubelike passage in the groin, called the inguinal canal, and descend into the scrotum. With an undescended testicle, that process stops or is delayed.
When to see a doctor
An undescended testicle often is found during an exam done shortly after birth. If your baby has an undescended testicle, ask how often exams will need to be done. If the testicle hasn't moved into the scrotum by 3 to 4 months of age, the condition likely won't correct itself.
Treating an undescended testicle when your child is still a baby might lower the risk of health problems later in life. These include cancer of the testicles and not being able to get a partner pregnant, also called infertility.
Older boys — from infants to preteens — who have descended testicles at birth might appear to be missing a testicle later. This might be a symptom of:
- A retractile testicle, which moves back and forth between the scrotum and the groin. The testicle might be easily guided by hand into the scrotum during a physical exam. A retractile testicle is due to a muscle reflex in the scrotum.
- An ascending testicle, which has returned to the groin. The testicle can't be easily guided by hand into the scrotum. Another name for this is an acquired undescended testicle.
Talk to your child's doctor or other member of their care team if you notice any changes in your child's genitals or if you have other concerns.
The exact cause of an undescended testicle isn't known. Genes, the health of the baby's mother and other factors might have a combined effect. Together they may disrupt the hormones, physical changes and nerve activity that play roles in how the testicles develop.
Things that might raise the risk of an undescended testicle in a newborn include:
- Premature birth or low birth weight.
- Family history of undescended testicles.
- Health conditions in the baby, such as cerebral palsy or a problem with the wall of the abdomen.
- The mother having diabetes before or during pregnancy.
- Alcohol use during pregnancy.
- Smoking cigarettes or exposure to secondhand smoke during pregnancy.
- Exposure to some pesticides during pregnancy.
The testicles need to be slightly cooler than regular body temperature to develop and work well. The scrotum provides this cooler place. Complications of a testicle not being located where it's supposed to be include:
Testicular cancer. Men who've had an undescended testicle have a higher risk of testicular cancer. This disease often begins in testicle cells that make immature sperm. It's not clear why these cells turn into cancer.
The risk is greater in men who've had undescended testicles located in the stomach area than in men who've had undescended testicles in the groin. The risk also is higher when both testicles are affected. Surgery to correct an undescended testicle might lower the risk of testicular cancer. But the cancer risk doesn't go away completely.
- Fertility problems. These problems make it harder to get a partner pregnant. They're more likely to happen in men who've had an undescended testicle. Fertility problems might be worse if an undescended testicle goes without treatment for a long time.
Other health conditions linked with an undescended testicle include:
- Testicular torsion. This is the twisting of the cord that brings blood to the scrotum. It's a painful problem that cuts off blood to the testicle. Without quick treatment, the testicle might become so damaged that it needs to be removed with surgery.
- Trauma. If a testicle is in the groin, it might get damaged from pressure against the pubic bone.
- Inguinal hernia. A part of the intestines can push into the groin through a weak spot in the muscles of the stomach area. The bulge this causes can be painful.