Dating scan

5 replies

Molly1001 · 13/09/2020 12:58

Hi can anyone help please, how inaccurate can a dating scan be, like how many days/weeks can they be out x

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TH22 · 13/09/2020 13:06

I suppose technically weeks if you have pcos/another reason for very irregular periods... if you can't pinpoint the exact date of your ovulation, then a dating scan could easily be out.

plixy · 13/09/2020 13:19

How many weeks did the scan say you were?
If you have a scan at say 6 weeks the baby is tiny and so harder to measure. At this point they could be a week or so out. Not weeks.
If you have the scan at 12 weeks it is much bigger and easier to measure and is therefore quite accurate.

Original poster

Molly1001 · 13/09/2020 13:21

@plixy I had my first scan on the 4th April and I was 9 weeks 4 days I’m trying to work out when I conceived approximately would these dates be based on my lmp or my conception date?x

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plixy · 13/09/2020 13:23

I just replied on your other post x

passthemustard · 13/09/2020 13:24

A dating scan at 12 weeks is pretty accurate.

An early can scan is not quite so accurate. My 6 week scan matched my dates but my dating scan showed I was 5 days further on than I thought.

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