See clip from Attorney Rajiv S. Khanna's conference call video that addresses this question.
You can apply for EAD. But USCIS has said they don’t like the idea of separating the applications as it can cause delays. Personally I think that’s baloney. I would file it if I were you. You have two options. You can premium the H-1 then H-4 gets premium. Kind of piggy bank on it and when the H-1 is approved file EAD as long as you have a receipt number. I don’t see why it should be a problem. So your choice I would file it.