Ultrasound mistake?

[lanababi]

I got an ultrasound 2 weeks ago on 11/11/10, and I measured 4.5 to 5 weeks. I had another ultrasound today, and I measures 8.5 weeks. That makes no sense! So in 2 weeks my baby jumped 3.5 weeks in growth? this can't be right! which ultrasound is more accurate? should I bring this up to my ob/gyn?

[Beccabb]

It's easy for them to get it wrong on the first one cos baby is so small, they told me I measure behind on my first one then on my 12 weeks one measured exact to my dates, is wait to see what you measure at ur 12 week scan n go by that

[lanababi]

Thanks for your response. I am just so confused because with my first pregnancy, all my dates matched up to the ultrasounds and I never had more than 2-3 days error.  

When I had my ultrasound on 11/11, there was just a gestational sac. No yolk sac and no baby or heart beat. So I couldnt have been more than 5 weeks along.So I am pretty sure that my ultrasound done today (11/29) is wrong. Because if i really was 8.5 weeks, then 2 weeks ago, i would have been 6.5 weeks, and a heartbeat/yolk sac would have been visible. I will certainly bring this to my doctor's attention at my next visit.

[LosingMyMindInGA]

I just went back and looked at your dates and they really aren't that far off and as previously stated early ultrasounds can be off by a week or so.  I would still talk to your doc for some reassurance tho.

[LosingMyMindInGA]

I would definately bring it up to your obgyn.  First trimester ultrasuonds are usually very accurate but it's not uncommon for them to be off by a week or so either way.  The discrepancies in your dates however are a little above average so I would def. speak with yoru doc.