tattoo_mama - Actually there has been quite a bit of research into essential oils & pregnancy, there are even aromatherapists who specialise in pregnancy.

Yes there are oils that are not safe during pregnancy, just like there are herbs not safe (like rosemary - in large doses), but if you talk to a qualified aromatherapist, then you should get correct information.

I'd be looking at text books used in aromatherapy studies instead of baby books for information on oil & pregnancy. Sal who owns the Perfect Potion chain has an amazing book on essential oils, it is actually used throughout the world as a text book, I've still got to unpack my uni stuff since my move so I can get my hands on it right away (am studying Bachelor of Health Science majoring in naturopathy), but if there is a Perfect Potion near you, you should be able to go and have a quick look at the book.