About 10% of people have an outie belly button, and the reason comes down to how the body heals after the umbilical cord falls off, not how the cord was cut or clamped. The shape of your belly button is essentially a scar, and like all scars, the final result varies from person to person.
How Belly Buttons Form
When you’re born, the umbilical cord is clamped and cut, leaving a short stump attached to your abdomen. Underneath the surface, the opening in your abdominal wall (called the umbilical ring) gradually heals and seals itself shut. Over the next week or two, the stump shrivels, dries out, and falls off. What’s left behind is your belly button.
For most people, the remaining tissue settles inward, creating the familiar hollow indentation of an innie. But for roughly 1 in 10 people, the tip of the cord’s remnant pokes outward past the surrounding skin, forming an outie. An outie typically looks like a small ring-shaped opening with a raised nub of skin visible in the center.
It’s Not About How the Cord Was Cut
One of the most persistent beliefs about belly buttons is that the doctor or midwife somehow controls the outcome by how they clamp or cut the cord. This isn’t true. The cord is always cut several inches away from the body, and the clamp sits on the stump well above the skin’s surface. None of that influences what happens at the deeper level where the tissue is actually healing. The final shape is, as one anatomy researcher at Washington State University put it, “a total wild card.”
The variation comes from differences in how each person’s body lays down scar tissue during healing. Some bodies produce a bit more tissue, some a bit less. The size of the umbilical ring, how quickly it closes, and the thickness of the surrounding skin and fat all play a role. Genetics likely contributes, though no single gene has been identified as the determining factor.
Umbilical Hernias Can Look Like Outies
Some outies aren’t just extra scar tissue. They’re actually small umbilical hernias, which happen when the abdominal wall doesn’t fully close around the umbilical ring. This leaves a gap where fat, fluid, or a small loop of intestine can push through, creating a soft bulge at or near the belly button.
Umbilical hernias are common in newborns and often close on their own by age 4 or 5. In adults, they can develop from anything that puts sustained pressure on the abdominal wall: heavy lifting, obesity, or repeated pregnancies. The key difference between a harmless outie and a hernia is how the bulge behaves. A hernia is soft and may change size when you cough, strain, or lie down. A regular outie stays the same regardless of what you’re doing.
Most umbilical hernias don’t cause problems, but certain symptoms signal an emergency: sudden sharp pain, a bulge that turns red or purple and feels firm, nausea and vomiting, or blood in your stool. These can indicate the herniated tissue has lost its blood supply, which requires immediate treatment.
When Innies Become Outies
Belly button shape isn’t always permanent. Pregnancy is the most common reason an innie temporarily becomes an outie. As the uterus expands, it pushes against the abdominal wall with enough force to pop the belly button outward. This typically happens around 26 weeks, during the second or third trimester. For most women, the belly button settles back to its original shape after delivery, though it may look slightly different than before.
Liver disease and other conditions that cause fluid buildup in the abdomen can also push the navel outward. When large volumes of fluid accumulate in the abdominal cavity, the abdomen becomes distended and taut, flattening or even pushing out the belly button. Rapid weight gain or significant changes in body composition can have a similar, though usually less dramatic, effect.
Surgical Options for Changing Shape
If an outie bothers you cosmetically, a procedure called umbilicoplasty can reshape it. The surgery is relatively minor. A surgeon makes an incision deep within the belly button, removes excess skin and fat, addresses any small hernias contributing to the bulge, and repositions the remaining skin so the navel sits slightly hooded inward. The whole thing is done under local anesthesia in most cases.
Recovery is quick compared to most surgeries. Most people return to work within one to three days, with sutures removed after one to two weeks. Swelling can linger for a few weeks, and exercise is typically off limits for about three weeks. The goal is to create a natural-looking oval innie, and for most candidates the results are permanent.
That said, outies are completely normal. They carry no health disadvantage and function identically to innies. The belly button itself has no biological purpose after birth. It’s simply the scar left behind from the one connection you had to your mother before you started breathing on your own.