I just found out today that USCIS will not accept any I-140 applications without the medical exam complete. This was just announced to my attorney from USCIS today. This is new. I imagine because they are expecting a flood of applications they want them to be complete.
Thankfully I just completed mine but it was hard to get it done. The closest physician I could do it through in time for July 2 was 2 hours away from my home and I ended up having to make the trip 3 times. The first time for the medical exam, 2nd time for TB check, and then noticed an error and had to make an additional trip today to get it corrected. I imagine I am not the only one who had difficulty getting the medical exam done in time.