Is there an Inyan of pregnant women walking over cut nails ex: a nail salon? Also, can I just vacuum up the cut nails from the floor?
The Mishna Beroura (260, 6) quotes Gemara Nidda (17a) disapproving someone who would throw nails on the highway after cutting them.
Indeed, a pregnant woman could step on them and lose her child.
Gemara's conclusion :
The practical advice is to throw them in the toilets because with modern ones it's considered as being buried.
Yes, Zahava, the gemara in Moed Katan 18 says that walking over nails can cause a woman to miscarry. One reason given (Be'er Hetiv/Tola'as Ya'akov) is because Chava caused the loss of "full-body nails". As a consequence, women are put in danger by the nails which remained on the fingers and toes.
The gemara gives options of how to dispose of them:
Vacuuming them would certainly fulfil the 2nd option. I'm not sure how far the 3rd idea goes and whether it would apply from one area to another area in the same salon.