When a fetus is in amniotic fluid, it mimics breathing motions without gas exchange happening in the lungs. So the fetus’s lungs are filled with amniotic fluid, no problem I guess. Except if an adult’s lungs are filled with fluid, even a relatively benign fluid, it’s tremendously difficult to clear them to allow normal breathing. That would be a medical emergency, and yet newborns have (relatively) no trouble taking that first breath. Obviously this works out fine in most cases, but I’m failing to see the mechanism that clears the newborn infant’s lungs of fluid to allow for air to flow. I could imagine a few scenarios that all seem unlikely. Don’t shake the baby and all that.
I guess I didn’t phrase that as a question. How is it that a newborn’s lungs empty themselves of liquid to a sufficient degree to allow for them to begin normal respiration?