1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  2. Hi Guest, welcome to the TES Community!

    Connect with like-minded education professionals and have your say on the issues that matter to you.

    Don't forget to look at the how to guide.

    Dismiss Notice

Dating scan accuracy?!

Discussion in 'Pregnancy' started by eightytwo, Jul 28, 2009.

  1. I had my first scan yesterday at what I thought was 11+4, calculated from my last period. I've been told i'm actually 14+2! Has anyone else experienced this? From reading quite a few posts, most people seem to move a couple of days not nearly 3 weeks. Can it be right/how accurate is the dating scan?
  2. I had my first scan yesterday at what I thought was 11+4, calculated from my last period. I've been told i'm actually 14+2! Has anyone else experienced this? From reading quite a few posts, most people seem to move a couple of days not nearly 3 weeks. Can it be right/how accurate is the dating scan?
  3. I can't say how accurate they are but my scan said I was 8+2 when I think I am 7+3 -all I can say is that is has caused my partner (who I have only just met and who I believe I became pregnant by on our first night -I know I know I'm old enough to know better) to run off claiming I am a cheating numpty trying to trick him into caring for another man's child -which isn't true.
    Have you gone back through your dates and double checked? I'm sure you have but that is all I keep doing.
    I hope someone can give you a more comprehensive answer but wanted to add my voice to your enquiry.
  4. Oh my god LRRS, now I understand your concern on the other thread! Are you going to get a second opinion? My mum and step dad conceived my brother (accidentally) on their first night together and they've been happy together for 17 years. I hope it works out for you!
    Re: dates, I am confused too because the sonographer didn't give me a new due date although she told me I was 11+3 when according to last period I was 12 weeks. Am I right in thinking I just move the old due date forward 4 days?! Sorry if that sounds thick!! [​IMG]
  5. Oh and she wrote on my notes that I would be 13 weeks on 18th July, which was 8 days after my scan when I was apparently 11+3!?[​IMG]
  6. My EDD changed by almost 2 weeks - at the dating scan they thought I would be12+4, but measurements showed I was actually 10+6. The first date was based on LMP (long cycle!), the second on measurements.
  7. The offical answer is that they are accurate to 4 days. On the other handI know many people who know when they conceived for various reasons. At the end of the day the measurements are just averages. Babies end up all sorts of sizes so it is likely that they will grow at different rates.
    I know that I conceived on one of 2 occasions in one week. I haven't worked out if those fit with my dates, maybe I will do that!
  8. Bsmirched

    Bsmirched New commenter

    I know my friend was measuring a couple of weeks ahead at 12 weeks, but is back to what she should be now, at 20 weeks. As others have said, there can be huge variation!
  9. Hi new to writing on here but have been reading lots of useful advice from you all. I know it is common to move dates by +/- 4 days and in this case they don't bother to change the dates on your records. Dating scans work on the assumption that the length of all babies in the first 14ish weeks progress at exactly the same rate. Which seems a bit odd to me considering that length of cycle, birthweight and everything about the mother vary such a lot. A friend of mine had her dates pushed back by about 3 weeks, only to have her baby 5 weeks 'early' but with no more complications than you would expect for a 2 week early baby, she is firmly convinced she was right all along!
    Sorry to hear it can put some people in such difficult situations.
    (I'm 21+6 weeks)
  10. they do move it by 4 days- they moved mine by 3 days.
  11. Guess it varies place to place, or my midwife doesn't trust the sonographer! She'd already written Dec 6 on my file the scan results say Dec 2 but they have left Dec 6 as the date for my MAT B1 form, lets face it, won't make any difference to when the little person decides to arrive!
  12. When I had my son, I was moved forwards by almost two weeks and despite what I said they refused to change it. When he was delivered by section at 37 weeks, he was apparently a typical 35 week old baby - small and very hairy! xx
  13. I have questioned this also. I know exactly when i conceived (can't be any other time unless i'm a medical marvel!) and now at both of my 8 week and 12 week scans, they have told me i'm almost 2 weeks ahead. I went into meltdown as this has implications for me also but my hubby assures me it just can't be when they said it is!
    I don't think it is exact. i must just be having a bigger baby!
  14. It is so frustrating! Thanks to the scan I had my partner has definitely walked away and is now calling for me to have a termination. I am in pieces but looking at the CRL I am at exactly 8+3 which is about 5 days further on and at a growth of 1mm per day I am going to just have to accept that maybe they are correct and somehow this is a miracle and super sperm have made my baby.
    I'm so pleased your hubby is supporting you -take care fo yourself and look forward to your beautiful baby
  15. I should have said a super sperm has made my baby - and me a biologist tut tut!
    Anyway I found this online
    From early on in pregnancy, babies grow at different rates, so these numbers are merely averages. Your baby's actual length and weight may vary substantially. Don't worry too much if an ultrasound indicates that your baby is much smaller or larger. (Your practitioner will let you know if it's time to worry about how big your baby is.) By full-term, your baby may end up weighing less than 5 pounds or more than 9.

    which gave me some relief.
  16. Hope this doesn't offend you LRRS, and believe me my husband can be a bit of a know, but seriously this guy is an idiot!
  17. Personally from my 3 pregnancies I reckon you as women need to go with what you believe - we're usually going to know best about our bodies. They usually get stuff wrong from the scans. My last bump was huge and from the extra growth scans I had they were predicting a 10 pound plus baby, right up until minutes before he was born (by section). He was 8 pounds 10!
    Sorry to hear about your situ LRRS. What a *****!
  18. I saw my midwife today who confirms that my EDD by LMP is 11th March but that EDD by scan is 8th March making me 3 days ahead. When I said I think I conceived later than when you are suggesting she said not to worry as these things even out in the end. However this is absolutely no help in convincing my ex who believes with all his heart this is an exact science.
  19. dating from midwives and scans seems a little bit variable! My scan agreed with my dates but when the midwife works it out on some circular thing the weeks vary so that she has put on my notes that i'm a week less than the hospital scan thought!! LRRS - aren't you very tempted to just say once more that it is his and then just smile sweetly - when the baby is born you can always get a DNA test for proof (and to make him feel like a total a@@e!!
  20. becky70

    becky70 Occasional commenter

    Maybe that's what he wants to believe. Sadly, you can't prove him wrong until after your baby is born. Hope you can surround yourself with people who will support you through your pregnancy and early days of motherhood. Good luck.

Share This Page