I had 3 month therapy too. DHEA as well. and in the 3rd month, I got pg naturally!
I was also taking: prenatal, wheatgrass, high doses of coq10, royal jelly, l-arginine, vit d, and calcium. I was doing acupuncture, yoga and trying to reduce stress (which is not easy with IF). I also had dropped gluten from my diet and most sugar and only eating antibiotic free, hormone free meats and organic veggies.
My RE monitored me on dhea. Is your sister getting monitored? You don't want to run your DHEA or free testosterone too high. Insist on blood tests!
It can happen!