In the last few months of a pregnancy, a baby goes through all kinds of changes. The eyes open wide, the bones fully form, and weight gain ramps up. For boys, it’s also when the testicles move from the lower belly to the scrotum, that pouch of skin below the penis.
But sometimes, one or both testicles don’t fall into place. That’s called an undescended testicle. It can happen to any baby boy, but it’s more common for those born earlier than expected.
More often than not, the testicle drops into the scrotum on its own by the time the baby is 6 months old. If it doesn’t, the child will likely need surgery.
What Causes It?
Doctors aren’t sure why it happens. They think it’s related to genes, the mother’s health, and outside influences that change how hormones and nerves normally work.
Even though the cause isn’t clear, certain factors might make an undescended testicle more likely:
- An earlier-than-expected birth
- Family history of them or other problems with how genitals develop
- Health conditions, such as Down syndrome, that affect how a fetus grows
- Low birth weight
- Contact by the parents with certain chemicals (pesticides) that kill bugs -- these are often used on farms
It may also be more likely if the mother:
How Do I Know There’s a Problem?
The main sign: You can’t see or feel the testicle in the scrotum. When both are undescended, the scrotum looks flat and smaller than you’d expect it to be.
Some boys have what’s called a retractile testicle. It may move up into their groin when they are cold or scared but moves back down on its own. It’s generally not a problem. The difference is that an undescended testicle stays up -- it doesn’t move back and forth.
In most cases, your doctor finds the problem as part of a regular check-up soon after birth.
If your doctor thinks there’s a problem, they may try to rule out other causes, such as:
Ectopic testicles. This is a similar condition where the testicles don’t fall into place. Your doctor can check for this as part of a physical exam.
Retractile testicles. Your doctor will see if they can gently move the testicle into the scrotum with their hand. If they can do that, then it’s a retractile testicle.
What Problems Can It Cause?
An undescended testicle is related to a number of conditions:
Fertility problems. Because sperm need to be a little cooler than the rest of the body, an undescended testicle can cause fertility issues. This is more of a problem when both are lodged in the groin. Early treatment can make a big difference.
Hernia. This is a condition where part of the intestine bulges through the muscles of the lower belly.
Injury. When the testicle is out of place, it’s more likely to be damaged.
Cancer. Men who have an undescended testicle are a little more likely to get testicular cancer, even if they have surgery to treat it. But surgery makes routine self-exams possible, so if cancer does appear, it can be found early.
Very often, the testicle moves into place within a few months. At first, you’ll want to wait and see how things go with regular check-ups. If it doesn’t drop into the scrotum by 6 months, your doctor will likely suggest surgery.
Surgery is the most common treatment, and it almost always works. It’s usually done when the baby is 6-12 months old to get the most benefit. Early treatment can lower the chances that your boy will have problems with fertility later in life.
An undescended testicle can also be treated with hormones. This isn’t the typical treatment though. It usually doesn’t work as well as surgery, and there may be side effects.