I didn't manage to find a yoga course that was convenient for me (pre-natal, in the evenings, and at a convenient location to get to after work
I have been going to a sports class though for the past few months, if this is what you are looking for. I'm happy with it http://www.mominbalance.com/switzerland/en/
Let me know if you end up finding a good yoga place. I'm getting closer to my due date though, so not sure I'm up for trying anything new soon...