Why is there a foramen ovale in fetus hearts?

Question

anonymous · Answer

Great :D stupid words now?

anonymous · Answer

i understand but i need to lock it in with some laymen terms

anonymous · Answer

"Stupid answer": Blood in a normal adult enters the heart in a deoxygenated state full of waste products, then enters the lungs for the release of waste and to pick up oxygen, goes back into the heart, and is then pumped back through the body to do it all again. In short, blood goes from the body to heart to lungs to heart to body.
Unborn babies do not use their lungs in this capacity because they're still in the womb (and can't breathe air), so the heart needs another mechanism for the transfer of oxygen and waste products. The foramen ovale and ductus venosus exist to by-pass the lungs and get oxygen/remove waste through the mother instead.