Final answer:
Approximately 1% of babies are born with knots in their umbilical cord, which is an essential structure connecting the fetus to the placenta for nutrient and oxygen supply.
The cord is cut after birth, leaving a stub that becomes the navel. Knots can pose varying degrees of risk, but such complications are rare.
Step-by-step explanation:
About 1% of babies are born with one or more knots in the umbilical cord. The umbilical cord, a long, narrow conduit containing two arteries and a vein, is essential for the development of the fetus as it connects to the placenta and supplies the necessary nutrients and oxygen.
Shortly after birth, the umbilical cord is double-clamped and cut, leaving behind a stub which dries out, shrivels, and falls off to become the navel after it fully heals. Knots in the umbilical cord can vary in seriousness, with some having little to no effect on the baby's health and others causing potential complications.
Notably, such occurrences are quite rare, considering the percent of babies affected by any kind of umbilical cord abnormality. It is also important to understand that a variety of factors contribute to the health of a newborn, and the majority of recognized complications are genetic, with the environment playing a lesser role.