DoTerra Oils during pregnancy

Emah
Hello! I love using DoTerra Oils; however, since I found out I was pregnant, I've been hesitant to use any (especially taking any orally). 
Are there any oils that are safe to use? My absolute favorite is the OnGuard. I'm a 1st grade teacher, and that's my go-to oil during cold and flu season. 
I've been using Peppermint and Digestzen for my nausea, which seem to be working well together. I'm not ingesting any of them, but I am applying them. 
If you're using oils, are there any oils that have been working for you? Please share.