Can ultrasound be off by almost 3 weeks??

[haley5915]

I went in for my first ultrasound yesterday expecting to be 8 weeks 2 days, and was then told I was measuring 5 weeks 3 days. This is my first pregnancy, so naturally I was/am very concerned, however, it seems like this happens a lot!! I had also just come off of the pill right before getting pregnant, so the dr seemed convinced that I had just ovulated later than I thought. Anyone have a similar situation?? I'm going crazy until my next visit next week!!

 

[Maries_s]

This happened often. I don't remember how many weeks I was in my first US with my DD but was definitely less weeks than I thought.

 

[MoBaby]

How long ago did you you get your first bfp? That would be important because then you would know roughly how far along you should be. For example if you got your first bfp 2 weeks ago you would be around 6 weeks preggo. For a pregnancy measuring 5w3d you would have just tested positive 10-14 days ago or so. If your first bfp was like a month ago and you're only measuring 5weeks 3days then that's not a great sign.
But measuring a week behind usually isn't a problem.
I assume 8 weeks is based on lmp? When was lmp vs day you got positive test?

 

[superfrizbee]

Yes, I too was going to ask when you got your bfp. It is possible for your cycles to be screwy after bc, but how long you've known would help determine how far along you should be.

 

[haley5915]

Thanks girls! My last period was Dec. 4 and first positive was Jan. 8, but very very faint on a First Response. The dr said to not analyze when the test was too much, because my cycle was probably very off. I'm preparing for the worst, but really hoping for a positive outcome next week!

 

[haley5915]

She also said that the ultrasound could be off 4+/- days which would help with the timeline

 

[rockstarlove9]

I went in for my first ultrasound yesterday expecting to be 8 weeks 2 days, and was then told I was measuring 5 weeks 3 days. This is my first pregnancy, so naturally I was/am very concerned, however, it seems like this happens a lot!! I had also just come off of the pill right before getting pregnant, so the dr seemed convinced that I had just ovulated later than I thought. Anyone have a similar situation?? I'm going crazy until my next visit next week!!

It may be just fine just try not to stress over it and see how next week turns out

 

[MoBaby]

So if your bfp was Jan 8th, Counting that day as 14dpo (around abouts since you don't know for sure) then Jan 8 is 4 weeks so today you would be around 7.5 weeks. I'd say anywhere from 6.5-7.5 weeks. You should have seen a heartbeat at this visit. At minimum a fetal pole and yolk sac. I think with you measuring so far behind I would be concerned. All you can do is go for the follow up to see how things turn out.

 

[Talia12]

If you had a vvfl on the 8th, let's say for example you were 7dpo (you wouldn't get a + any earlier). That would have made you 3 weeks pregnant, which would make you about 6+2 at your scan (if I'm calculating correctly, maybe another lady can check?!) So to be measuring 5+3 you're a week or less behind. That could be ok.
I say push the doctor a little bit on the point about when you got your BFP - they're used to dealing with women who have little to no idea how it all works, so they just brush those concerns off with "well you ovulated late". Make the point that you really could NOT have ovulated any later than 1st Jan, or you would not have got your BFP on the 8th.
Fingers crossed for you!

 

[Talia12]

I agree with pp in that you would be around 6.5 weeks. You probably weren't 14dpo on the 8th if it was a vvfl. I got mine at about 8dpo

 

[luz]

Happened with 2 of my pregnancies, but I was only off by 2 weeks. One I thought I was 10 and ended up 8, another thought I was 8 but was only 6

 

[veganmum2be]

It depends on the size on the sac. New rules about how to assess a blighted ovum are that the sac needs to measure 25mm or more or (18mm in Transvahinal ultrasound) before they can say for certain that the pregnancy won't develop.

It could be your uterus position. It doesn't seem too positive but it's worth having a bit of hope i'm going through something similar at the moment.

 

[Cooking.No.2]

In my first pregnancy I was measuring 2 weeks behind apparently and my due date was 26/12. I had my baby 25/12 and had emergency c-section and it turned out he was over cooked by two weeks. So I would say measurements aren't always correct with everyone. Good luck sweetie xx

 

[icegurl470]

I got an early positive this time around, like 9dpo, I conceived on cycle day 21 less than a week before my expected period. If you conceived super late in your cycle, that alone could put you at 2 weeks ahead where they thought you were based on lmp, couple that with the u/s tech being a week off in their measurements (which is easy to do that early on because a fraction of a cm can change the gestational age by days) and that could explain it. Did they see a heartbeat? Have you had any bleeding? It doesn't sound like your dr is concerned so that's a good sign.

 

[boobee]

With my first child I had an early ultrasound at what I thought was 7 weeks to be told I was 5 (had bleeding). I had no idea when I actually ovulated due to my periods being all over the place. I went for a follow up a week later and was told I was 6 weeks (8 weeks by my dates).. however when I went for my dating scan at what they said was 12weeks I was actually measuring 14 so my dates were always correct. Baby must've just been measuring small to start with. I ended up delivering 9 days early too. I think at the very early scans they can be off.