Hannele,
The best person to ask if you could get pregnant is a reproductive Endocrinologist.
There are lots of women with CAH that birthed children.
Do you know what type of surgeries that you had? Because that would help me anser one of your questions easier as normal is different for many people but it's had to gage what you are talking about because within CAH is a spectrum of different surgeries that may or may not be needed. Someone that is older that had a clitorectomy, urethraplasty, and vaginoplasty would have a different view then someone else that had something else or at a different age.
I'm not a doctor and my uneducated guess that taking Dex wouldn't make a difference.
If anything- it might be something not related to CAH that might cause you not to get pregnant that easy like your thyroid for example.
Good luck with everything.
