What stops babies/mammals fetus’s lungs from filling with Embiotic fluid while in the womb?

Question

Additionally, what triggers a baby, once exiting the womb, from taking its first breath?

In: Biology

Answer 1

The lungs do fill with fluid, but it doesn’t matter as they aren’t using the lungs in the womb the oxygen comes through the cord, the reason why they want babies to cry when they are born is to show that they are using the lungs for the first time.