The Ins and Outs of Belly Buttons

By Howard J. Bennett

Whether you have an innie or an outie, most people take their belly button for granted. After all, what’s it good for except trapping lint, sweat, and other icky stuff? Well, that may be true now, but the next time you look at your belly button, remember that it once played a very important role in your life.

Before you were born, you spent nine months growing in your mother’s body. Little kids think babies grow in their mom’s stomach, but if that were true, babies would be digested like a piece of cheese! In reality, babies grow inside a special organ that women have called the uterus. (Babies are called fetuses before they are born.)

During the pregnancy, fetuses can’t eat or breathe in the traditional sense. They still need oxygen and nutrients, however, and the uterus is designed to provide them. Soon after the developing fetus attaches to the inside of his mom’s uterus, something called the placenta begins to grow. A short time later, the fetus begins to develop the umbilical cord that will attach to the placenta.

The umbilical cord is made up of a tough jelly-like material called Wharton’s jelly. Lying within the cord are three blood vessels—two arteries and one vein. At the time of birth, the umbilical cord is about 20 inches long and ¾-inch thick.

The umbilical cord is a biologic highway that enables the fetus to grow. Oxygen-rich blood and nutrients travel from the mom’s body into the fetus. Oxygen-poor blood and waste products travel from the fetus back to the mom’s body. The mom gets rid of the baby’s waste products through her lungs and kidneys.

After a baby is born, he is still attached to his mom’s placenta via the umbilical cord. Blood will continue to travel back and forth for a few minutes after birth. In some cultures, the blood vessels are allowed to stop flowing on their own, after which the cord is tied off. In other cultures (like ours), the obstetrician or midwife will attach a plastic clamp to the cord thereby interrupting the blood supply between mom and baby. After the clamp is applied someone cuts the cord.

Things aren’t over yet because the placenta is still inside the mom. So while parents and baby are getting acquainted, the obstetrician or midwife patiently waits for the placenta (afterbirth) to be delivered. Because the placenta is filled with lots of blood vessels, it looks like a big piece of raw meat. Nowadays, hospitals dispose of the placenta; in the past, some cultures buried (or ate them) for good luck.

The umbilical clamp is left in place for about 24 hours, and then the nurse removes it. The baby is now left with something referred to as an umbilical stump, a brownish lump that’s consists of dried out Wharton’s jelly and its contents. In most cases, the stump falls off in a week or so.

The grownup name for the “defect” that’s left in the baby’s abdomen after the umbilical stump falls off is the navel. But to you it’s known as the belly button. And a cute one at that!

© 2012 Howard J. Bennett. All Rights Reserved.
(First published in the Washington Post 11/16/09.)

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