Have You Ever Wondered Whether Your Belly Button Is an Innie or Outie? Here is why.

The belly button, or umbilicus, is a uniquely universal feature of the human body. Every single person possesses this small, often overlooked scar—a testament to the earliest connection with life itself. There are those of us who have deep, sheltered belly buttons, and those who have more pronounced, outward-protruding ones. Most of the time, we merely refer to these distinctions as “outies” or “innies.” The differences are often a source of curiosity and speculation, leading many people to develop interesting, if entirely incorrect, beliefs on how each kind of belly button is formed.

Though the ideas around our belly buttons can seem interesting when you’re relaxed, they rarely provide any useful or accurate information. Surprisingly, the scientific explanation for why our belly buttons appear the way they do is quite straightforward, rooted entirely in the process of scar formation and, occasionally, minor structural variances in the abdominal wall. The truth debunks one of the most persistent myths of human anatomy.

I. The Great Belly Button Myth: Debunking the Umbilical Cut Theory

The most common theory about the formation of the umbilicus, held by countless people globally, is tied directly to the hospital room immediately following birth.

The Myth vs. The Reality

Most people mistakenly think that the manner our umbilical cords are severed determines the form of our belly button. The idea suggests that a “good” or tight cut by the doctor or nurse results in a neat innie, while a “bad” or loose cut results in an outie.

The Reality: There is absolutely no validity to the notion at all. The final shape of the umbilicus is determined by natural biological processes happening inside the body and during the healing process, not by external cutting.
Irrelevant Cutting: The umbilical cord itself, which transports blood and nutrients during gestation, is essentially a flexible tube with no nerve endings. It is clamped and cut several inches from the baby’s body. What remains is a small stump. This stump dries out and breaks off naturally within one to three weeks after birth. The state of your belly button is defined by what happens after the umbilical cord is severed, specifically how the tissue seals and heals.

The Scar Tissue Factor

The umbilicus is, anatomically, a scar. It is the remnant of the ring where the umbilical arteries and veins entered the body.

Scar Development: Whether this scar tissue becomes an innie or an outie depends largely on how it develops and retracts after the cord stump dries out and breaks off. The process is entirely internal and unique to the individual’s skin and abdominal structure.
Final Loss of Significance: The fate of the belly button’s appearance is sealed when the final bit of cord dries out and breaks off. The resulting scar tissue either retracts inward, creating a depression (an innie), or pushes slightly outward, resulting in an outie.

The Prevalence Statistic

Innumerable studies confirm that innies are far more frequent than outies. Approximately 90% of the population has an innie, making the outie a much rarer anatomical feature, though both are completely normal.

II. The True Causes of an “Outie”: Hernias and Scar Protrusion

If the way the cord is cut does not determine the shape, what actually causes the remaining scar tissue to protrude outward? The answer lies in two primary, natural causes.

Scar Protrusion

The simplest cause for an outie is the way the scar tissue itself forms during the healing process.

Excess Tissue: When there is minimal excess scar tissue remaining, or when the skin naturally puckers and protrudes slightly during the final sealing process, an outie develops. This is a normal variation of scar formation and is purely aesthetic.

Umbilical Hernia: The Common, Benign Cause

The more common, and often misidentified, cause of a protruding belly button is an umbilical hernia.

The Hernia Mechanism: An umbilical hernia occurs because the baby’s stomach tissues (specifically, a small loop of intestine or fat) protrude through the belly’s muscular fibers at the umbilicus. Normally, the muscular opening where the umbilical cord passes through closes completely shortly after birth. When these muscle fibers do not close entirely, the pressure from the abdominal cavity (such as from crying or coughing) pushes the tissue outward.
Frequency and Safety: Unbeknownst to the general public, umbilical hernias are considerably more common than one might think, and they are typically not as dangerous as they sound. In infants, the vast majority of umbilical hernias are benign and resolve on their own, often closing completely by the time the child is three or four years old.
No Discomfort: Crucially, the infant experiences no discomfort since this specific condition has no accompanying pain. If the hernia is small and resolves spontaneously, the result is often a slightly protruding scar—the “outie.” Only in rare cases, if the hernia is large or fails to close, is surgical intervention required.

III. The Dynamics of Aging: When an Innie Becomes an Outie

The shape of the umbilicus is not fixed for life. As the body changes, so too can the appearance of the belly button, primarily due to rapid and extreme changes in the surrounding abdominal volume.

Pregnancy and Obesity

Pressure on the Abdominal Wall: As we age, our little innies may become outies, particularly during periods of rapid and sustained weight gain or extreme abdominal expansion. An innie may become an outie if the stomach grows rapidly due to pregnancy or obesity.
Stretching the Scar Tissue: The expanding uterus or the rapid accumulation of visceral fat places immense outward pressure on the scar tissue and the already-stretched abdominal wall. This pressure forces the depression to flatten and sometimes push outward, temporarily or permanently converting the innie into an outie. This change is purely mechanical and cosmetic, representing a stretching of the fibrous tissue.

IV. The Umbilicoplasty Trend: Cosmetic Correction

In modern cosmetic medicine, the belly button is no longer simply a scar but a feature of the body subject to aesthetic modification.

The Desire for the Innie

It may surprise you to learn that many people pursue cosmetic surgery (umbilicoplasty) to alter the appearance of their belly button.

Aesthetic Goal: The vast majority of people who seek cosmetic surgery do so to transform from an outie into an innie, reflecting the social preference for the recessed umbilicus. The procedure involves surgically tightening the skin and deep tissue to create a more defined depression.
Correction After Pregnancy: Umbilicoplasty is also frequently performed as part of a tummy tuck (abdominoplasty) procedure, particularly for women post-pregnancy, to restore a more youthful or aesthetically pleasing shape to the umbilicus after it has been stretched or altered.

V. The Significance of the Umbilicus: A Lifelong Reminder

The belly button, whether an innie or an outie, represents a profound connection to the body’s earliest origins. It is the one scar we all share, marking the place where we were physically attached to our first source of life.

Now that you have more factual knowledge about your belly button—understanding its origin as a scar, debunking the myth of the umbilical cut, and recognizing the simple causes of the “outie”—be sure to share this information with all of your friends.