What is it in antidepressants drugs that causes a women to loose their sexual desire?

The antidepressant.: There is nothing in them per se. The antidepressants each are single chemical compounds which depress sexual desire by altering nerve transmission in the brain and probably exert a secondary reduction in desire by inhibiting orgasm.

Serotonin effect: If sppropriate for your circumstances, ask your doctor if wellbutrin might be an option for you. It works on different receptors. Another option is cymbalta, (duloxetine) but wellbutrin would be my first pick. Good luck and best wishes.