I would not worry about this at all unless you are having problems too. My ds went a full 15 days without a poop at about 6 weeks or so...we were worried, but we talked with his Naturopath and his GP and they both agreed that if he was peeing ok, bfing ok, behaving normally otherwise and showing no specific senstivity to his tummy/intestinal area that we were fine. In fact, his Naturopath said that he probably just had a super healthy and effecient system. They did make sure that I was having regular bm's, though. Since that was the case, my naturo said, "you're eating well, he's eating well...obviously there's just not a lot of waste". So hang tight...
You can: eat lots of stool loosening foods: papaya, macadamia nuts, deep greens and LOTS OF WATER and peppermint tea (aids constipation, among other things) and gently massage baby's belly after a bath.
If you reach a point where you are really worried, our GP said that an ultrasound of his belly wouldn't be out of the question to make sure that there was no blockage or anything. We didn't ever reach that point, but it seemed like it would be a reasonable next step.
Good luck and enjoy the easy diaper duty!!! believe me, you'll look back fondly at this stage when he's taking three poops a day!!