At our clinic, the minute you report a pregnancy, they want you in for a blood test, weight, etc. and a meeting with a nurse. She thought I was farther along than I was, so I went in for an U/S as well the next week, though we found it was too early to see a heartbeat. So that's 2 visits (plus a third for another blood test) before 6 weeks!
That said, so long as you're taking vitamins, and you're healthy and all that, I really don't see why you should have to go in this early, though. Both visits were pretty uninformative for me, and it was a pain lining up child care. If I'd left it all until 8 weeks, it would have been a lot more efficient. I've just had a bad history of loss, so I'm a tad paranoid, and it did help (somewhat) with that for me.