About 10% of people have an outie belly button, and it has nothing to do with how the umbilical cord was cut or clamped at birth. The shape of your navel is determined by how your body heals after the cord stump falls off, along with the structure of the tissue underneath. Several factors can create that outward protrusion, some present from birth and others that develop later in life.
How Your Belly Button Forms
During pregnancy, the umbilical cord connects through a small opening in a baby’s abdominal muscles. After birth, the cord stump dries out, shrinks, and changes color from yellowish-green to brown to black before falling off on its own, typically within one to three weeks. The baby feels nothing during this process because the cord has no nerves.
Once the stump detaches, the small opening in the abdominal wall is supposed to close as the surrounding muscles knit together. What’s left on the surface is your navel. Whether it ends up as an innie or an outie depends on how the underlying tissue heals and how much scar tissue forms, not on anything the doctor or midwife did with the clamp and scissors. As developmental biologist Sarah Brigham-Althoff at Washington State University put it, how your belly button looks at the start is “a total wild card.”
Umbilical Hernias: The Most Common Cause
The leading reason a belly button pokes outward is an umbilical hernia. When the abdominal muscles don’t join together completely along the midline after birth, a small gap remains. Tissue or a loop of intestine can push through that gap, creating a soft bulge right at the navel. In babies, this bulge is often visible when the infant cries or strains and may flatten when they’re relaxed.
Most umbilical hernias in children close on their own by age 4 or 5 as the abdominal wall strengthens. Adults can also develop umbilical hernias, especially with conditions that increase pressure inside the abdomen, like obesity, repeated heavy lifting, chronic coughing, or fluid buildup in the abdominal cavity. An adult umbilical hernia is less likely to resolve without treatment.
When a Hernia Needs Urgent Attention
Most umbilical hernias are harmless, but a hernia that becomes trapped (incarcerated) is a surgical emergency. If tissue gets stuck in the opening and can’t slide back in, it creates a firm lump that doesn’t go away. You may notice redness or swelling at the site, nausea or vomiting, severe pain in the lower abdomen, or difficulty having a bowel movement. The most dangerous scenario is when the trapped tissue loses its blood supply, called strangulation, which requires immediate surgery.
Umbilical Granulomas in Newborns
Sometimes a newborn’s belly button doesn’t fully heal after the cord stump falls off. Instead, a small, moist lump of pink or red tissue forms at the base of the navel. This is an umbilical granuloma, and it’s very common, painless, and generally harmless. The exact cause isn’t known.
A granuloma can make the belly button area look puffy or protruding and may produce a small amount of discharge. Left untreated, it can take months to resolve. With treatment, the granuloma typically shrinks within two to three days, changes color, dries out, and heals. If you notice an offensive smell, redness, or significant discharge around the area, that could signal an infection rather than a simple granuloma.
How Pregnancy Changes Belly Button Shape
Many people who’ve had an innie their entire life are surprised when their belly button pops outward during pregnancy. The reason is straightforward: as the baby grows, the expanding uterus pushes against the abdominal wall from the inside. Think of inflating a balloon. As the surface stretches tight, any indentation gets pushed flat or outward.
This change is most likely during the third trimester, roughly weeks 28 through 40, when the abdomen reaches its largest size and internal pressure peaks. For most people, the belly button gradually returns to its original shape after delivery, though the timeline varies. Significant weight gain outside of pregnancy can create the same effect, as excess abdominal fat increases internal pressure against the navel.
Can You Change an Outie?
An outie belly button is a cosmetic variation, not a medical problem (assuming there’s no hernia involved). But for people who want to change the appearance, a procedure called umbilicoplasty reshapes the navel. It’s most commonly considered by women after pregnancy or by people with scarring from a belly button piercing.
Recovery is relatively quick. Most people return to work within a day or two, though exercise needs to wait a few weeks. Stitches come out about 7 to 10 days after surgery unless dissolvable sutures were used. If you’re planning a future pregnancy, it’s worth knowing that the abdominal stretching involved can undo the cosmetic results.
The Short Version of What Shapes Your Navel
Your belly button’s shape comes down to how your body healed after the umbilical cord detached, whether the underlying abdominal wall closed completely, and how much scar tissue formed in the process. Factors that can create or contribute to an outie include an umbilical hernia (the most common structural cause), an umbilical granuloma in newborns, pregnancy, and significant weight gain. The cord-cutting technique plays no role at all.