I am on H-4 visa and my husband is on H-1 visa since 2008. We have an approved I-140 and have applied for a three year extension on the basis of approved I-140 on May 8, 2015, but we have not got any confirmation from USCIS yet, so my concern is that can I apply for a H-4 EAD before our visa extension is approved.
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.