Early Ultrasound Big Date Change

[WaturMama]

I had an ultrasound at what I thought was at 7w2d today and was proclaimed to be 5w4d--given a photo and a hearty, "Congratulations!" There was a heartbeat, at the right rate and the fetus and sac both matched that new date.

On one hand I am so happy to see a heartbeat--we haven't seen one on a first u/s since we had our ds. That was how we found out 2 pgs weren't viable, once at 11.5 weeks, once at 7 weeks.

On the other hand those new dates don't make much sense to me. If that were true I got a BFP at 4 dpo (I thought it was 16 dpo), which I don't believe is possible. The BD timing is quite a stretch, too.

Has anyone else had something like this happen? Any words of wisdom?

[L J]

I chart, religiously. So, I knew my exact O date. I went in for an early u/s and was pretty much told it was a blighted ovum, though there was no offer of meds to abort, she wanted to wait a week and see. Went back, and I should have been over 7 weeks and I was measuring 8 days behind what my O date would indicate. Studying my chart, I do believe it to have been very late implantation.

I am 20+ weeks right now with a healthy little girl, and she is still measuring according the the early u/s date, not my date.

Words of wisdom? No, not really. The next few weeks are going to suck, coming from a BTDT perspective and a PAL perspective. I hope these weeks pass quickly and you can find some peace while you wait to see what plays out. You are in my thoughts mama - I hope you just had a late implantation.

[akind1]

Ultrasound dating is not an exact science, they can often be off by a bit. Granted, early ultrasounds are supposed to be more accurate than later ones for dating, but even so, there is a margin of error.

With this pregnancy, my 2nd, my 1st ultrasound at what I figured to be 8 weeks (give or take a couple days) I measured almost 7 weeks, so off by about a week. Actually, when she first measured, I think she was more like 6 weeks . . . and asked if that sounded right. DH and I were like, Noooooo, so she remeasured and gave us 7 weeks, exactly a week behind where I know we were. Which I am ok with actually, since DS was 2 weeks "late" (induced at 41+6 - for dates only, there were no other complications, ended up with a c-section), I like the extra week of breathing space for this baby to arrive.

I took a test at 14 DPO, which was on of the least sensitive you can get - a plain Answer sensitivity is like 100 miu's I think - and it was positive, but not strongly so. There is no way that it would have been positive at 7 DPO, if I went by U/S dates.

at any rate, you saw a heartbeat! such a good sign. and there is a margin for error with the early ultrasounds, so take that into consideration also.

[moona]

Sorry, no words of wisdom; I dont know what to say about the dates.. maybe a combination of late implantation and ultrasound inaccuracy.

But.... YAY for a healthy little heartbeat!!

[BHappy]

Originally Posted by moona 

Sorry, no words of wisdom; I dont know what to say about the dates.. maybe a combination of late implantation and ultrasound inaccuracy.

But.... YAY for a healthy little heartbeat!!

hugs!

[WaturMama]

Thanks so much for the replies.

LJ and aKind1, it is a relief to see some similar stories, and I am so glad to hear your pregnancies are going well.

LJ, I see you are in Alabama, thanks so much especially for answering yesterday--I hope all is as well as possible. I also relate to the charting religiously part. I've been doing it for over a decade and my dates have never been off before. I think that is part of why I feel so discombobulated by this. It is maybe a good reminder to embrace some more of the mystery.

aKind1, very interesting that the tech changed the prediction by a whole week based on your reaction. I read somewhere in my obsessive internet surfing last night, that the 5-7 week u/s are less accurate than ones a little later.

moona and BHappy, thanks so much for stopping by!

I am feeling calmer today, partly thanks to all of you, and focusing on that heartbeat.

[MarineWife]

I'm surprised they gave you dating of only 5w4d after seeing a heartbeat. A heartbeat is usually not seen before 6w. At 5w4d, you would only expect to see an amniotic sac and maybe a yolk sac and fetal pole. Based on that, I'd bet the measurements were off some. They are very subjective and can be off by a week or more even in the early weeks when they are supposed to be more accurate.

Once you see a heartbeat the likelihood of there being a problem drops dramatically. I would hang on that rather than the measurements.