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a question about pregnancy scans
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a question about pregnancy scans

I've read so many times about ladies having a scan to measure the size of the baby and being told that they are not as far along with the pregnancy as they thought they were?

Why would this be?  I thought that if we knew the first day of our last period then the age of a developing fetus would be correct?

So I'm assuming I am 7 weeks pregnant because I know the date of my LMP and the date of ovulation, so would I be predicting the fetal age correctly?  so many questions but I don't understand why dates get changed after a scan.

thanks for any replies
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603463_tn?1220630455
Hi!
My best answer to your question is that all of the dates you are given, by all of the methods available, are ESTIMATES.  Different women have cycles of different lengths, so the pregnancy wheel, or computer calculators are only based on the average cycle.
Ultrasound is user dependent.  Twisting the transducer by a millimeter or two can change the due date by a day or two, even in a very early scan--much more so in later scans.

When most doctors determine a due date (Estimated Date Due EDD or Estimated Date of Confinement EDC) they combine all of the best available data so that there is a starting point to use to observe how things change as time goes by.

I hope this makes a little sense.

Only your baby knows when he/she is going to be born!  And he/she will not tell you until then!

Good luck!
Dr B
3 Comments
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1167212_tn?1264186347
Thankyou very much Dr B
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i was just wondering if you could tell me if once you have a scan at 8 weeks and see a strong heart beat does the rate of mc drop? i keep reading it does on the net5 but i would be gateful to hear it from someone who knows about this thanks
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