Our belly buttons, a small indentation or protrusion on our abdomen, are a universal human characteristic. While often considered a mere aesthetic feature, this mark holds a fascinating story about our earliest beginnings. Many people wonder about its actual purpose, which is tied to the intricate processes of human development.
Before Birth: A Lifeline’s Role
Long before birth, the structure that eventually forms the belly button plays a crucial role in a developing fetus’s survival: the umbilical cord. This flexible cord connects the fetus to the mother’s placenta, an organ that forms in the uterus during pregnancy. It acts as a lifeline, facilitating a continuous two-way exchange of substances.
The umbilical cord contains three blood vessels: one umbilical vein and two umbilical arteries. The umbilical vein transports oxygen-rich blood and essential nutrients, such as glucose, amino acids, and fatty acids, from the placenta to the fetus. Conversely, the two umbilical arteries carry deoxygenated blood and metabolic waste products, including carbon dioxide and urea, from the fetus back to the placenta to be processed and eliminated by the mother’s body. This intricate circulatory connection effectively functions as the fetus’s lungs, heart, and gastrointestinal system, as its own organs are not yet fully developed to perform these tasks independently, making this continuous transfer essential for proper fetal growth.
After Birth: A Vestigial Mark
After birth, the umbilical cord’s role concludes as the newborn’s own organ systems become functional. Healthcare providers typically clamp and cut the umbilical cord shortly after delivery, leaving a small stump attached to the baby’s abdomen. This remaining stump, which is painless for the baby, then undergoes a natural drying process.
Over the course of one to three weeks, the umbilical cord stump darkens, shrivels, and eventually falls off. The small wound left behind then heals, forming the belly button. Unlike its prenatal function, the belly button no longer serves an active biological purpose. It is considered a vestigial structure, a physical reminder of the connection that once existed between the developing individual and their mother.
Why They Look Different
The varied appearance of belly buttons, whether an “innie” or an “outie,” or differences in size and shape, is primarily a result of how the scar tissue forms after the umbilical cord stump detaches. This healing process is largely a matter of chance and natural variation. Factors such as the amount of skin remaining, individual healing characteristics, and the way the scar tissue contracts contribute to its unique look.
An “outy” belly button, which protrudes outward, is often a small umbilical hernia. This occurs when the abdominal muscles around the belly button do not fully close, allowing a small portion of tissue to push through. While it can appear as a bulge, this type of hernia is usually harmless and often resolves in infants. The appearance of a belly button is not influenced by how the umbilical cord was cut or how the stump was cared for.