Typically unless there is a complication or possible problem, most Dr.s dont' do them until at least 8 weeks. I had my first this time around at just over 6 weeks. It was to date the pregnancy as I had not had a period between last m/c and this pregnancy. Otherwise she would have done it at 8 weeks unless there was bleeding or reason to suspect an etopic pregnancy.
REs here do them at 6-8 weeks. OBs though usually wait until you are around 12 weeks.
I had mine just the other day- shy of 11 weeks. BUT- I wish I had been sent sooner- but they won't (here) before 8 weeks- unless you might be having ectopic or problem. In the past- I have had an ultrasound (transvaginal) at about 8 weeks- but before that I dont think there is really much to see anyhow.
HTHS
I had one at 5 weeks and it left me with nothing but worry because they weren't yet able to see the heartbeat. I was at a fertility clinic so they routinely scan for problems very early on. The next one was at 6 weeks (routine - found the heartbeat) then 9 weeks because they thought I might have gallstones so I guess since they were there they checked on the baby. After that I had the NT scan at 12 weeks then the anatomy scan at 19 weeks. The little bean wasn't cooperating and they couldn't get a good view of the spine, so we had to go back at 21 weeks. I think I'm done with u/s's for a while now.
Thanks for all the information it really helped.
I had my first at 10 weeks then at 18 weeks for the anatomy but she was stubborn and we couldnt get all the measurements so I had to then come back for a followup and do the anatomy again (all normal) at 24.5 weeks pregnant. Good luck :)
My first one was 5w6d, then again at 6w6d and we were able to see the heartbeat.