My LMP date wasn't wrong, I just ovulated WAY late. I too had an u/s at what should be 7 weeks based on my last menstrual cycle and no fetus or heart beat was detected - only the yolk sac.
When I went for my 2nd ultrasound I got to hear the heartbeat. The u/s tech said it appears to be more like a 5 week pregnacy.
They tested my HCG levels within a 48 hour period and they are not increasing as rapidly as they should.
I was worried and did not understand how I could be almost 2 weeks behind.
When I went in the technician said it was just too early and said I was only 5 weeks along and she showed me the yolk.
I went in for a 7 week ultrasound because of spotting.
Last week had my second scan at what they said should be my 8th week, turns out I have a retriverted uterus (harder to look round as it was an internal scan) by this scan they would like to find a heartbeat, they found it hard to find anything and just after they decided to tell me I had misscarried and broke my heart "oh wait we can see the yolk sac" thanks for that one!
I knew I wasn't 8 week pregnant and tried to explain this to the nurse, I knew I was around only 6 week.
My point is doctors should really listen to us before they go assuming we should be so far pregnant and start worrying us by saying they havnt seen what they would like to see developing at the stage that they think we are, ladies we know our bodies don't let these things worry you, just give more time and things should be fine.
I just wanted to let you all know that I was indeed a little over a week behind.
The first trimester is defined as the first 13 weeks of pregnancy following the last normal menstrual period (some authors refer to early pregnancy as 0-10 weeks).
It can be divided into a number of phases, each of which has typical clinical issues.