PCOS is just another symptom of estrogen dominance.  It generally is more prevalent in over weight women if they don’t have it because of CAH and the reason over weight women are more prone is because the more body fat a women has, the higher her estrogen levels as fat cells make estrogen.  Insulin sensitivityI think is just another side effect of obesity in women.  So it comes cap in hand with PCOS I’d say.  

As I have explained about estrogen dominance above you may be interested in that post regarding cervical dysplasia.   

The reason CAH women are predisposed to such is mainly because all sex steroids are raised when they are under treated, and this means there is often an imbalance between estrogen and progesterone.  Often you will find that they are making more estrogen via the third steroid pathway (where testosterone is made) rather down the other pathways.  It’s a little more difficult to treat that PCOS in women that are over weight because I’d say that their steroid pathways have not developed in the same way that a woman without CAH has.    For example, I don’t know what the ratio is of estrogen to testosterone a woman makes exactly---I’m not a Doctor and just ponder these things--- but for arguments sake lets say its 10:1 meaning she makes 10 times more estrogen than testosterone.  Now lets say men make it 10:1 testosterone to estrogen.  So they make ten times more testosterone to estrogen.  What makes us think that a woman born with CAH whom has had her outer genitalia affected has not developed somewhere half way inbetween or almost close to the ratio that a male produces such?

I mean I can’t see how the development of hypothalmus is not also influenced by the over exposure to androgen in utero.  It seems absolutely impossible to me that it would not.  The only way I feel to try to correct that scenario is not with synthetic hormone replacement but rather natural progesterone to balance things and to foster acceptance of ones condition.  In having studied the side effects of such drugs as progestins or synthetic estrogens, frankly the mind boggles as to what can happen when a woman is given them on a permanent basis.