Congratulations.  I am also pregnant with our third child, 9.5 weeks.  I have 2 daughters, the oldest one (2.5 years) with CAH.  With my second pregnancy I took the Dex as soon as I found out I was pregnant and I had a CVS at 12 weeks.  As it turned out, we were having a girl and she did not have CAH so I was weaned off the Dex.  The only side effects I had were increased appetite (thus increased weight gain!!) and also sleeplessness.  I am taking the Dex again and having these same side effects, and I am booked to have a CVS done in a couple of weeks.  The CVS for me wasn't pleasant the first time and I am not looking forward to another one, however I would much prefer to get the gender and CAH results as soon as possible rather than wait until an Amnio can be done at a later date.  I have heard from other women who have had a CVS done and it has just been mildly uncomfortable, I guess it depends on who does it!

Best of luck with the Dex and the remainder of your pregnancy.