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Pregnancy

Talk about every stage of pregnancy, from early symptoms to preparing for birth.

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Original poster

early scan showed 5+6 a week ago but only 6+3 today

26 replies

yellowflowers · 27/04/2010 19:16

Hi,
Had early scan because of some spotting last week and they saw a heartbeat and dated it at 5+6. Had another today and they took ages (it was awful - thought they were going to tell me they couldn't find anything) and then finally found the heartbeat but it measured at 6+3. As it is exactly seven days since last one it should have been 6+6 - anyone know the margin of error and if this is okay? I have to go back for another one next week but am so worried I don't know how I will get through week.

Anyone else had this?

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cyanarasamba · 27/04/2010 19:19

There is definitely a few days margin of error either way on these early scans. They are trying to measure something very small (less than 1cm), using a manual process. I wouldn't say a 3 day discrepancy on the 2nd scan is anything to worry about in itself.

Fingers crossed for a smooth pregnancy from now on!

MumInBeds · 27/04/2010 19:19

Don't let it worry you, with the sizes you are talking there only a couple of mm would make the difference and that can easily happen if the sonographer measured from slightly different places each time. The fact the heart has been bating for a week is a very positive sign.

Original poster

yellowflowers · 27/04/2010 23:08

Thank you both. Dh and I trying to stay positive and to believe the best. Hopefully will get a clearer idea at the next scan. Good that it will be a bank holiday weekend so we can spend some time together doing nice things.

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Original poster

yellowflowers · 28/04/2010 11:20

bumping this up in case anyone else knows about margin of error

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PrivetDancer · 28/04/2010 11:24

I think it's 5 days at that stage.
Had a similar early scan myself that showed much earlier than i thought, she measured the length three times and got a different measurement each time.. It's really just a few blurry pixels they're measuring isn't it!

The fact that they found a heartbeat is great.

I'm not having another scan til my 12 week one now, I think these early ones cause more stress than reassurance. At 12 weeks the dating is fairly accurate I think.

Good luck!

oopsandbabycoconut · 28/04/2010 11:25

How accurate is the scan at estimating the gestation?

In the first trimester (the first fourteen weeks), ultrasound scan is very accurate, with a margin of error of only about three or four days either way. The accuracy reduces as the pregnancy advances and may be out by as much as one week at eighteen to twenty weeks.

From the pregnancy bliss website. I had a scan at 7weeks (my dates) and they measured me as just 6 weeks. I had another scan at 9w3d (my dates) and baby measured 9w3d so there was clearly a margin of error at this point.

Original poster

yellowflowers · 28/04/2010 11:47

Thanks. You are so right privetdancer and hello - totally know your name from ttc threads and so pleased you are here as am I. I def felt more stressed than reassured yesterday.

Thanks oopsandbabycoconut - margin of error of 3-4 days okay as I was expecting 6.6 and they said 6.3. Have one more scan next week and hoping that will be what I was expecting. Trying to relax until then and am eating lots of yoghurt for calcium so it grows big and strong!

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vmcd28 · 28/04/2010 11:51

hi there, I was measured at 6w1d, then 1w3d later, I was dated at 9weeks. I said, "Oh I was expecting you to say I was 8w4d?" and she said, "Oh, these early scans are just to give you a rough idea that things are ok - the date I give you has a margin of error of 1 week."
The point is, the baby is tiny at the moment, and they have to magnify the image by many many times. So if there measurement is even a fraction of a mm out, then that could affect the dates by at least a few days.
Best of luck.

greenbeanie · 28/04/2010 11:52

Yes the scans can definately be out by a few days. I had my 12 week scan yesterday, by my dates I was 12+2, according to the sonographer 12+6 which means I conceived before I ovulated!!

vmcd28 · 28/04/2010 11:53

also, if they had been concerned, then they would have told you so - thats their job.

Original poster

yellowflowers · 28/04/2010 12:24

that's what my dh said. He reckons the doctor said all looked fine, heartbeat looked okay and not to worry and that they would say it if they meant it because it's their ethical duty not to give false hope. I still burst into tears as we left though! I feel pretty sick today - am delighted though as think this is good sign.

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WhiteRoses · 28/04/2010 12:37

Hi,

Not read through whole thread but just to say, I was dated 6+5 at my first scan. My next two scans gave the same due date, which put me at 7+3 on the day of the first scan. I was told that the reason for the big difference was that at 6/7wks, the baby is really curled up and hard to measure, so estimated dates at that time are normally pretty unreliable.

Hope that helps.

MumInBeds · 28/04/2010 13:10

Remember that 3-4 days is a margin of error on each scan so on the first then baby could be measured slightly bigger than he or she is and on the second slightly smaller so between the two scans you could have up to 8 days 'out'.

Enjoy your bank hol weekend and try not to worry.

Original poster

yellowflowers · 28/04/2010 13:25

Thanks Mumsinbed - except first scan was bang on what I expected it to be.

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rachxx · 28/04/2010 14:28

heya, the sonographer told me its +- 5 days, so dont worry too much. i had a can a week ago and they aid it was 5+5 and so today it hould have been 6+5 but they said it was more like 7 weeks, xx

ShowOfHands · 28/04/2010 14:33

And if you aren't reassured yet...

I had a scan that put me at 5+3 (I knew categorically that I wasn't, knew when I conceived) and then 10 days later, the scan agreed exactly with my dates. The error with the first scan was 5 days.

Really seeing a heartbeat and everything developing as expected is v good news indeed.

HappyGirl1 · 28/04/2010 14:41

Ladies so good to see this thread.. I had my first scan yesterday at what I thought was 8 weeks 3/4 days.. The MW measured it as 7 weeks 2 days and honestly I've been in a state of panic ever since. When I was looking at the picture though last night i do think that the baby is quite curled up (good to read here that that's normal too) so I'm holding out hope that at my 12 week scan they may surprise me and say that I'm 13 weeks. Once the baby is okay though I don't mind. I was in tears when she said she could see the heart beat flicker. Unbelievable.

legallyblond · 28/04/2010 14:52

I don't know about the margin of error (but agree with the above - the baby is seriously tiny and is magnified many many times to be able to measure it manually) BUT.... I do know that once you have actualy seen a heartbeat (as opposed to just a sac), the likelihood of an mc is significantly reduced. Once its in there with a beating heart, it really is very unlikely that something will go wrong.

Also, please don't forget that, unless you conceived by assisted means, it is very likely that you could be out on your ovulation date by a few days. I always went on ew mucus (not v reliable!) but even those ovulation indicators are only a guide.

vmcd28 · 28/04/2010 14:59

also, conception/ovulation/implantation dates can all vary from person to person. It is an average of 8-10 days after ovulation that implantation occurs, but could be anything from 6-12 days, so that can have a bearing on your own dates being wrong, even if you know to the day when you "conceived".
All the figues you read online assume that everyone has a 28 day cycle, and ovulates on day 14. In most cases, it is give or take a few days.

ShowOfHands · 28/04/2010 15:02

vmcd is right. I've never had a 28 day cycle. I ovulate on day 11 for example. I know when I ovulate (can feel it) and I know when implantation started (I have spotting around the time of implantation). So I knew what my dates were. Thankfully, once the baby was bigger and easier to measure, our dates agreed.

HappyGirl1 · 28/04/2010 15:28

That's all really good to hear. Just another 4 weeks 6 days for me to wait now for 12 week scan. Feel like it's going to be the slowest time ever. But hopefully will be worth it in the end.

Original poster

yellowflowers · 28/04/2010 19:20

thank you - I do feel much better. Have got another scan a week today and then the 12 week one is booked for 11 weeks as we'll be on holiday for week 12 - so just four weeks 2 days for that!

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Original poster

yellowflowers · 04/05/2010 10:20

For anyone experiencing same - wanted to tell you that we had to have another early scan due to more bleeding - so had it at UCH epu this weekend, and all was good and measurements were exactly what I expected them to be! So the second scan which was a few days out was, well, a few days out.

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PrivetDancer · 04/05/2010 12:32

That's great news (not about the bleeding obviously)
got my scan on Friday - aagh.

addictedisinthesecondtrimester · 04/05/2010 12:51

yellowflowers, just in case you still arent reassured i went along at 8 weeks for a scan was told baby was measuring at 5 weeks with a really strong heartbeat, i went back 7 days later and was told i was measuring at 7 weeks. then 4 weeks later when i had my 12 week scan i was told that i was 'almost' 11 weeks.

there is a huge margin of error especially if baby is moving about or curled up. and remember they have to use the mouse to click from one end of the baby to the other and 1mm can mean a week! so a sonographer with a shakey hand can potentially get it worng.

dont stress. good luck with your next scan. if they weret worried about it, neither should you be

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