Early scan dating

ttcttc · 2023-03-21T13:15:20+00:00

Has anyone had an early scan and given a different date to what they suspected and then it's changed later? I thought I was 8+4. But early scan dated 7+6. I know it can be somewhat of a guessing game that early. They didn't seem concerned and there was a heartbeat but still threw me a little.

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Tryingtoconceivenumber2 · 21/03/2023 13:40

Yes on DC1 I was moved from 13th of the month to 16th at a private scan at 10 weeks. On NHS 12 week scan they moved me to 18th of the month and DC1 arrived on 20th in the end all was well x

Original poster

ttcttc · 21/03/2023 13:50

@Tryingtoconceivenumber2 so both times you weren't as far on as originally thought?

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Blue2020 · 21/03/2023 14:17

Yes, I went for a private scan at 9+1 (I measured ovulation-opk and bbt) and they dated me at 8+5. So three days behind ovulation.

By the nhs dating scan they put me forward two days. So instead of 13+3 they put me at 13+5. (Technically before I ovulated but it’s close enough). Now I’ve switched to just saying the nhs date.

Apparently at the early gestation even 5 days can be a typical difference due to the accuracy/size etc. If it’s going off lmp it could be a larger gap. I ovulated on day24, so I just said an estimated lmp for the private scan based on ovulation.

Original poster

ttcttc · 21/03/2023 14:29

@Blue2020 I think I ovulated day 14. I don't really understand it all though 🤦🏼‍♀️

I just thought I was further on than they dated me but obviously they'll know better than me.

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KDxOx · 21/03/2023 14:38

Yes! I went for an early scan where I thought I would be 7 weeks and was dated 6 weeks 5 days. I wasn't too worried by a couple of days as they're often a bit out when you're looking at tiny measurements that early on and there was a good heartbeat.

When I went for a private "11 week" scan as part of a Harmony test package (I chose the date based on the 7 week scan), I was surprised to find out that I was 11+6, dates confirmed again at the 12 week NHS scan the following week.

It means that my early scan actually measured me 6 days behind!

Original poster

ttcttc · 21/03/2023 14:57

@KDxOx ah so I could be where I thought. I was only 5 days behind but just seems so long when I feel I've already been pregnant for months lol.

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KDxOx · 21/03/2023 16:17

@ttcttc Yes, you could well be - I see people measuring behind often when they have an early scan, to be caught up again at their 12 week dating scan.

Perhaps assume you're a couple of days behind where you thought you were originally and hopefully you'll get a nice surprise of being further ahead come 12 weeks. 😊

sommeliermama · 21/03/2023 17:06

I am 18 weeks now and have done a total of 4 private scans (I know it's a lot!) and obviously my 12 weeks NHS scan and all of them have given me different dates ranging between 18th and 24th August. It hasn't bothered me at all. I will think of it as more of a due week than a due date!

I think when the baby is still so small in the first couple of months a millimetre difference in measuring on a scan makes a big difference to your expected due date and leaves lots of room for human error, so try not to worry

Original poster

ttcttc · 21/03/2023 17:18

KDxOx · 21/03/2023 16:17

@ttcttc Yes, you could well be - I see people measuring behind often when they have an early scan, to be caught up again at their 12 week dating scan.

Perhaps assume you're a couple of days behind where you thought you were originally and hopefully you'll get a nice surprise of being further ahead come 12 weeks. 😊

They dated me five days behind already. They didn't seem concerned I think I'm just anxious after a mc

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Original poster

ttcttc · 21/03/2023 17:19

sommeliermama · 21/03/2023 17:06

I am 18 weeks now and have done a total of 4 private scans (I know it's a lot!) and obviously my 12 weeks NHS scan and all of them have given me different dates ranging between 18th and 24th August. It hasn't bothered me at all. I will think of it as more of a due week than a due date!

I think when the baby is still so small in the first couple of months a millimetre difference in measuring on a scan makes a big difference to your expected due date and leaves lots of room for human error, so try not to worry

Yeah I've read that elsewhere too. Sonographer didn't seem concerned anyways and the heart beat was there.

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Tryingtoconceivenumber2 · 21/03/2023 17:25

@ttcttc yes they did. I can only assume it was because DC was a tiny little 6lbs 1oz born but absolutely fine x

Original poster

ttcttc · 21/03/2023 19:19

Tryingtoconceivenumber2 · 21/03/2023 17:25

@ttcttc yes they did. I can only assume it was because DC was a tiny little 6lbs 1oz born but absolutely fine x

I'm maybe just not as far on as I thought.
Aww, What a dot 🥰

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Greensage · 22/03/2023 07:40

Congratulations on your pregnancy!

You're not sure which day you ovulated and you can't know when the egg implanted, which can be anything between 6-9 days. Added to that the measurement can be slightly off. So I can see how it can easily measure 5 days behind by what you calculated.

Greensage · 22/03/2023 07:42

If I recall correctly once you've seen a heartbeat statiscally the odds of ending up with a baby are 90%? I don't remember exactly but quite high.

Original poster

ttcttc · 22/03/2023 08:40

Greensage · 22/03/2023 07:40

Congratulations on your pregnancy!

You're not sure which day you ovulated and you can't know when the egg implanted, which can be anything between 6-9 days. Added to that the measurement can be slightly off. So I can see how it can easily measure 5 days behind by what you calculated.

I ovulated day 14.

I'm not too fussed being 5 days behind just wondered if it was normal or a worry

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Theduchy · 22/03/2023 09:06

I had scans at 7, 8, 10 and 12 weeks because of previous losses. All gave a different date and everything was absolutely fine 🙂 at that gestation you're talking about something so tiny that a millimetre out in measurements can make a big difference to dates.

Original poster

ttcttc · 22/03/2023 09:28

Actually I've just checked and it was cd12

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Original poster

ttcttc · 22/03/2023 09:30

Theduchy · 22/03/2023 09:06

I had scans at 7, 8, 10 and 12 weeks because of previous losses. All gave a different date and everything was absolutely fine 🙂 at that gestation you're talking about something so tiny that a millimetre out in measurements can make a big difference to dates.

I had a loss in December so think I'm just overthinking. Hopefully be okay for me too. Did you end up being later or earlier than you think? I know it doesn't matter I'm just being nosy lol x

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leanneb94 · 22/03/2023 10:10

I had a private scan when I was 9 weeks, they measured spot on for 9 weeks exactly. When I had my 12 week scan I would have been 12+2 but was measuring at 13+1 on this one.

Original poster

ttcttc · 22/03/2023 10:32

leanneb94 · 22/03/2023 10:10

I had a private scan when I was 9 weeks, they measured spot on for 9 weeks exactly. When I had my 12 week scan I would have been 12+2 but was measuring at 13+1 on this one.

It's a minefield isn't it. Hopefully know more at 12. I haven't got my app through yet.

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