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Pregnancy

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

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Original poster

Dates confusion

12 replies

Lyndz123 · 27/09/2013 10:19

Basically me and my husband went for our 12 week scan and baby measured 11 weeks 3 days which was 3 days behind my lmp. The date baby measured from was the 27th april which meant i ovulated on the 11th may right? Well we never had sex that day, we did the day after and a few days after that. But i read that measuring the CRL for gestational age was very accurate in the first trimester. I am really confused as i know for a fact there was no sex on the 11th. My EDD is the 1st of Feb

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K8eee · 27/09/2013 10:22

Hi lyndz, you can conceive up to 7 days after having sex I believe. I'm so confused with all the dates that I'm trusting what the sonographer has said even though it would mean I had a full blown period the week after baby was conceived. Congrats too!

lilstar · 27/09/2013 10:26

I was confuses about my dates as well as my 12 weeks scan put me a week ahead of lmp date. Apparently at that point they can be 3-5 days out. I now figure I ovulated a few days early and my scan is 3 days out. It sounds like maybe u concieved on the 12th and ur scan is maybe just a day out...that would be my guess anyway.

fanjodisfunction · 27/09/2013 10:27

The embryo may have implanted a little later in your uterus, there are lots of reasons, and to be honest your only a couple of days out. I was a whole wee out and only had sex once due to the flu. But in the grand scheme of pregnancy it really doesn't matter.

Congratulations.

BillyGoatintheBuff · 27/09/2013 10:29

I was totally flummoxed at my dating scan as it did not match up to my dates. I found that they wouldn't listen to me either when I was telling them when we conceived. But anyway it felt like such a big deal at the beginng of the pregnancy and it did worry me, but i am happy to report that by the time you get to the end of the pregnancy a few days discrepancy doesnt seem to matter so much at all. they like to go by their dates that are written down but all births occur whenever they occur regardless really. Some of us give birth before our dates and some after - at the end of the pregnancy it doesn't feel a big deal :)

SeriousStuff · 27/09/2013 12:54

I had a few early scans due to health worries (all was fine) and was put back on dates on three separate occasions! Throughout my pregnancy though, the baby has been growing well, but now at the end of my 3rd trimester, I'm measuring 2 weeks small but assured that everything is fine.

At the beginning, you just can't be sure when implantation took place, and at the end, it's just not very scientific!

SeriousStuff · 27/09/2013 13:03

...forgot to add, working out my dates form the first day of my last period, I'm due on 4th Oct but scans etc. put me at 12th!

MissCalamity · 27/09/2013 14:54

With DS1 my due date from my LMP was 16th December, at the 12 week scan they put me forward by a whole week, so 9th December, great I thought if I went 10 days overdue I'd be induced before Christmas.

As it was he arrived in 15th December, he did have a large head!

Can't wait to find out what due date I'll get in two weeks, eekk!

Anothermrssmith · 27/09/2013 17:15

I honestly have no idea what my due date is! First scan dated me at 9+6, my LMP put me at 12+2. Having lots of scans as diabetic and at what would have been my 12 week scan (which was done when I was 13 weeks) I suddenly jumped up to 16 weeks! At my 20 week scan I was told I was measuring small and booked for a growth scan 2 weeks later, at which point I was told I was actually only 20 weeks! To complicate matters I had bleeding before I got a positive test which, as we were trying to conceive, I thought was implantation bleeding but if that was actually a period it matches up with me only being 20 weeks at my last scan!

So now, if anyone asks, I say i'm due in January and don't get any more specific than that!

NomDeClavier · 27/09/2013 17:52

I systematically measure 3 days ahead of my dates. Happened with DS, happened with this one. Both times I had to have conceived after they said I did - with DS DH wasn't even there when I apparently conceived and this one was supposedly conceived Good Friday, which is a day of abstinence and obligation and DH was away all week until the Friday evening!

So it's really not that reliable.

Original poster

Lyndz123 · 28/09/2013 16:06

Thank you. I was just so confused as i know we only had sex on the 12th but going by the ultrasound it would be the 11th. I don't think i'll ever understand it. I take it from scan dates no one will ever know when they conceived unless they only done it once which we done it quite a lot that week as we were in honeymoon. So could it have been any od those days in that week? I thought u conceived exactly 14 days after gestational age??

OP posts:

NomDeClavier · 28/09/2013 18:27

That's an educated guess based on implantation - but the thing is even a millimetre at the stage can put you out by a week and it depends how good the person scanning you is.

FoxyRoxy · 28/09/2013 18:48

Babies in utero grow at different rates, just like they do after they're born. An ultrasound is not going to tell you when you had sex, it tells you the size of your baby based on averages of that gestational age. Adding to that it could be up to 5 days out either side to account for measuring inaccuracies and your scan date could be more than a week out from what you expect it to be. When you're 40 weeks it really won't matter :)

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