I recently gave birth to a daughter (non CAH). Our first daughter has CAH and I started the Dex when I was about 5 weeks pregnant.  I was told that the genitals begin forming at about 6 weeks so the sooner the Dex can be started the better.  I had no side effects whatsover from the Dex.  I took it until I was 15 weeks when we found out our unborn daughter was non CAH (I had a CVS at 11 weeks).   I would not hesitate in taking the Dex in future, however some women do have side effects, some minor and some more substantial.  I guess every woman is different and the Dex may effect women in different ways.

Good luck.