ELI5: Explain Like I'm 5

Lanugo

Lanugo is a special kind of hair that babies grow while they are developing inside their mommy's tummy. This hair is very soft and fine, almost like feathers! Lanugo helps to keep babies warm and protect their skin while they are growing.

However, most babies shed their lanugo hair before they are born, and they have thick and healthy hair when they are born instead. Sometimes, babies are born with a little bit of lanugo hair still on their body, but it usually falls off within a few weeks after they are born. So, think of lanugo like a warm and cozy blanket that babies have while they are growing in their mommy's tummy!