The belly button often sparks curiosity about its varied appearance. Many individuals wonder about the formation of an “outie” navel, particularly whether its shape is passed down through families.
Understanding “Outies”
The umbilicus is the scar left after the umbilical cord is clamped and detaches following birth. This cord, which connected a baby to the placenta, shrivels and falls off within one to three weeks. An “outie” belly button is characterized by skin or scar tissue that protrudes outward from the abdomen, giving it a convex appearance. This contrasts with the more common “innie” navel, where the skin indents inward. About 10% of newborns develop “outie” belly buttons.
Are “Outies” Genetic?
“Outie” belly buttons are not determined by genetics. While genetic factors influence many physical characteristics, the appearance of the navel is primarily a result of the umbilical cord stump’s healing process. The way the skin and scar tissue form after the cord detaches largely dictates whether the belly button will be an “innie” or an “outie.” Therefore, its shape is a matter of chance, not an inherited trait.
The True Causes of an “Outie”
The formation of an “outie” belly button is primarily influenced by the umbilical cord’s healing and resulting scar tissue. Variations in how the stump shrivels and detaches, and the amount of scar tissue formed, can lead to an outward protrusion. Excess scar tissue around the navel area can cause the skin to project outward.
Another common cause for an “outie” is an umbilical hernia. This occurs when abdominal muscles around the navel do not fully close, creating a small opening through which intestines or fatty tissue may bulge. Umbilical hernias are common in infants, affecting about 20% of newborns, and appear as a bulge that becomes more noticeable when the baby cries, coughs, or strains. While they can result in an “outie” appearance, most umbilical hernias in children are harmless and resolve on their own. Rarely, an umbilical granuloma, a small, reddened mass of tissue remaining after the cord falls off, can also cause an “outie” by preventing the navel from fully indenting.
When to Seek Medical Advice
While most “outie” belly buttons are normal and do not pose health risks, certain signs or symptoms warrant medical evaluation. Consult a doctor if the navel area shows signs of infection, such as foul-smelling discharge, redness, or swelling. Persistent bleeding after the umbilical stump falls off should also be checked.
For those with an umbilical hernia, seek medical attention if the bulge becomes painful, tender, or discolored. Other concerning symptoms include the “outie” significantly increasing in size, or if the child experiences discomfort, vomiting, or constipation, which could indicate a complication like trapped intestine. Most umbilical hernias close naturally by the age of four to five years; however, if a hernia persists beyond this age or causes issues, surgical repair may be considered.