The CVS is performed earlier in pregnancy, so results are quicker, which is an advantage but the test itself is slightly more risky regarding miscarriage than an amnio - as any doctor will tell you.  I lost a baby girl through the CVS test, who I later found out was not affected by CAH.  I was advised to go for the amnio for my next pregnancy (wouldn’t have agreed to another CVS anyway) and had to take the dex throughout as the result showed another CAH affected  girl. The dex did make me put on more weight than expected but although my second daughter with CAH will still require surgery at puberty (as the labia is still fused), the operation will be minor compared to what her sister had (reduction of clitoris too).  I therefore feel I made the right choice (for me!) but realise everyone is different.  Difficult decision - good luck!