Q: What is the umbilical cord?

A: The umbilical cord is a narrow, tube-like structure that connects the
developing baby (also referred to, in medical terms, as the fetus) to
the placenta and transports blood and nutrients between the fetus and
the placenta. The umbilical cord is sometimes called the baby’s “supply line” because it delivers the nutrients and oxygen the baby needs for normal growth and development and removes waste products.

The umbilical cord begins to form about five weeks after conception. It becomes progressively longer until about 28 weeks of pregnancy, reaching an average length of 22 inches. As it gets longer, the cord generally twists around itself and becomes coiled.

Inside the umbilical cord are three blood vessels which are are protected by a surrounding gelatin-like tissue called Wharton’s:

  1. Two arteries transport waste from the baby back to the placenta (where waste is transferred to the mother’s blood and disposed of by her kidneys).
  2. One vein carries oxygen-rich blood and nutrients from the placenta to the baby