tzaddiq- I believe the problem with cutting nails on Motzei Shabbos is that it shows a lack of kovod to Shabbos. If thet needed to be cut it shouldve been done before Shabbos.
In regards to pregnant women and cut nails, the potential hezek is only if she steps on them in the place where they fell. If they are swept across the room there is no problem. (This is based on a Gemora, I forget where it is)