system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5 How do newborn babies expel all the fluid in their lungs after they are born?

The inside of a womb is full of fluid. As the fetus matures within the womb, it’s lungs should not have any air inside of them right? So, when the baby is born, how does the baby expel all of the fluid from its lungs in order to breathe air?
gpt
To start, when a mother is pushing, the birth canal compresses the lungs and fluid can be expelled out.

After, when a baby is born, it coughs and breathes! Over a couple hours, all the fluid is cleared out either by coughing the fluid out forcefully, air replacing the fluid in the lungs, or by the baby's body re-absorbing the fluid.