Quoting Fiddlesticks[Liamishere!]:" <blockquote><b>Quoting Vindictive:</b>" No wait, did she?! It's sterile until ... [snip!] ... c section because your baby will breath it in. I had one done because they thought my son had swallowed some in the womb."
Because when the baby poops in the womb, they make sure that they clear the nose and the mouth much faster from fluid so the baby doesn't take their first breath with meconium in mouth/nose. It's not an issue until they actually take a breath outside of the womb. And it's not always the case that they have to give you a c-section, a lot of doctors just make sure to suction the babies nose/mouth as soon as the head is out.