Stephenie Meyer has berkata that, Edward did notice it, but , kind as he is, he never berkata anything , atau even complain, though it caused him additional pain. Bella , on the other hand, was too ashamed to ask him whether that caused him a problem atau not... So they both kinda ignored it :P
Stephenie Meyer called it 'dead blood' and it therefore does't have the same appeal as Bella's actual blood would however it is difficult for Edward during that time. However he would never mention it as he's such a gentleman.
According to the Twilight Saga: The Official Illustrated Guide, Edward is aware of what's going on physiologically with Bella, but he is too much of a gentleman to ever say anything about it, and Bella would be too embarrassed to ask if he noticed atau was bothered oleh it. The blood from a woman's period isn't the same as a cut; it's not freshly oxygenated, not flowing from the heart.