EDD accuracy

[Lyndz123]

I have been confused about the EDD i was given since my dating scan. I am now 26 weeks and still confused. My lmp started on the 24th april but dating scan said it was the 27th? This gave me an EDD of 1st Feb but i counted back and that would mean i ovulated on the 11th May but we never had sex on this date or before this date. The 11th was our wedding day. We had lots of sex on honeymoon the following week but if we conceived then does that not mean my EDD would be later? Also we went for a HD scan a few days ago and that said EDD (AUA) 6th Feb 2014 which to me would be about right but i've been told later scans arent accurate

TBH you might be right but the baby will come when it wants anyway! My DS1 was 11 days late so really it's just a guestimate if I were you I would think sometime early Feb! My EDD was Jan 26th he came Feb 11th

Does it matter especially to you for work our something??

As I understand it, the EDD from the dating scan has a margin of error of +/- 5 days. And there is only 5 days difference between the two dates you have mentioned (1 feb and 6 feb) so it all sounds fine to me. There's only a few days in it.

Focusing on a precise date is likely to send you mad IMO- much more relaxing to think of a due "date" which is 5 weeks l

Argh, fat fingers!
...5 weeks long, since the baby could arrive any time between 37 and 42 weeks gestation and be considered on time.

Like you, I know my edd from the scan is a few days early (we were using ov predictor kits and also to have conceived as early as scan puts it would have required an immaculate conception...). I am just keeping a note of my dates in case there is argument over dates later on (hoping for a vbac, hospital policy is repeat section rather than induce if overdue, those 4 days could become more significant later on for me). Hopefully neither of us will need to worry about it though!

Estimated due date is just that an estimation, it is usually give or take 5 days, so it does make sense giving the dates you think you conceived don't worry too much as another said you will be full term from 27 weeks,

I was just about to start a thread on the same topic. We just had our dating scan today which puts me at 13+4 - a whole week later than I KNOW I am.

How do I know?

I was using a ClearBlue Fertility Monitor (in the mornings) AND Boots Ovulation Predictor Kit (for the evenings) AND I was tracking my Basal Body Temperature AND tracking my cervical fluid. All of these methods clearly point to my ovulation date being on day 21 (I have always ovulated late).

According to today's scan, I ovulated closer to day 14, 2 days before BEFORE my oestrogen started to rise, 6-7 days BEFORE my LH surge (which I can tell you started sometime after 7am on day 20 and was evident in my urine by 7pm), 7-8 days before a thermal shift was detected in my BBT and with a week's worth of fertile cervical fluid yet to come (with a clear change in fluids around day 21)

It's driving me insane that the scan is SO off - mainly because I'm hoping to have a VBAC this time around, and they don't like to let you go too over your due date esp if you had a big baby last time around, so this dating can make or break my chances of a VBAC (even though I know I can refuse to go by their dates...but I will be advised to have an ELCS if and when I go 'over'??)

Anyway I've lost all faith in dating by scans today. Would love to hear from anyone who had a similar experience!!!

I read that dating scans are extremely accurate. Which is what is confusing me.

EDD stands for ESTIMATED due date.

What does it matter 5-7days difference ? Only 5% of babies are born on their EDD any way so your best to look at it as PP said 5weeks due date 37-42 weeks

GreenGiant, it matters when hospitals have policies of inducing or treating you as high risk (therefore reducing options such as midwife led care in a home birthing unit) when you go X days over your due date.

You are absolutely right, due date does not predict birth date. However when I had DD1, I was treated as though I turned into a pumpkin at midnight when I turned 42 weeks I was immediately transferred to the hospital labour ward as I was suddenly classed as high risk. Fine if my due date was accurate, but if my due date was 1 week too early my options would have been more limited unnecessarily.

My EDD has been changed 3 times so far. I have had to have numerous scans already (19 weeks at present) and each time I'm scanned my EDD is bought forward by another few days

I'm dwelling on anything though as babies grow at different rates and will arrive whenever they want to anyway

This is probably the only reason to be happy about IVF - I know my dates for sure :-)
Good luck with VBAC ladies - I hope you get the births you are hoping for.

Chill Winston :)

A few days here or there really doesn't matter.

I knw babies grow at different rates after 12 weeks but my baby measured 11 weeks 3 days at my dating scan and 9 weeks 3 days before that we never had sex. It was after then, so why was baby measuring from then?

Both times they've put me ahead of possible conception dates. You can argue for expectant management no matter what your hospital policy says. I just plan on going past when they would like to induce until we reach my dates.

I started my period on 27th of jan My lmp edd puts me at 2nd of novemeber and
I had an early scan at 8 weeks 6 days and put me at 11th of November? Which is more accurate and does it mean I've ovulated later than usual

The sonography told me they’re only accurate to 4 days either way, they’re an estimation based on measurements. I counted back from my due date and it’s before my lmp which doesn’t make a whole lot of sense. Also worth remembering it depends on when you ovulated and also sperm can live for up to 5 days so conception is impossible to say 100%