Well it is kind of a process and I'm sure for different people there are different experiences. I was out of town at 4wks pg, so I went to RE when I got back at just under 5wks pg (3wks post IUI). My HCG was 161. RE was immediately concerned because he said my HCG should be around 100 at 4wks pg and then double every 48-72 hrs. He had me come back every other day for HCG and u/s. At six weeks at my HCG was only up to 1300 and he couldn't find a sac in my uterus. If i remember correctly, at 1500 they should definitely be able to find something and sometimes between 1000-1500.
So I guess the answer is, have them monitor your HCG to see if the levels are good and verify sac is in the uterus as soon as possible. Usually sac can be seen on u/s between 5 and 6 wks. And of course, I'm no dr, this is just what i learned from my experience.
BTW, have you heard anything back from babemuneca? Her situation is so similar to mine. I'm very interested in how it turns out. Since she hasn't been around, it might be sign things are going well???
Thank u Hannah. I will follow ur advice since I have a gut feeling this is going to wind up in a ectpic one (if something happens ofcourse) since my fall... tube was swollen