ultrasound scans...

[Danielle]

Hi there girls,

Now, I am just wondering... about ultrasound scans, I know they aren't overally accurate for your due date and all. But I had a scan at 6 weeks to find out my due date, its the first thing my doctor sent me for, he said the earlier the scan the more closer to the due date they will get?

However this 6 week scan showed I was due on the 11th April. And I had another scan (which was meant to be the routine 12 week scan) at 14 weeks, because thats when I could get in here, and my due date showed 20th April? Thats a difference of 9 days which isnt that great. And my OB at the hospital said they take it on the scan closer to the 12 week one cause its more accurate? I am hearing different things from everywhere.

Another thing is he's been turned upside down since 27 weeks too, which made mw think it was a little early compared to my last (she turned at 34 weeks), and his head is already starting to engage, and I am 32 weeks (going by the due date of the 20th) - When I could possibly be 34 weeks which sounds a little more right?

Does anyone know which scan is meant to be more accurate I dont wanna be freakin out if he decides to come, and I would be thinking he is premmy cause of my due dates being wrong - when in fact he could of been coming on time if you get what I mean?

What have your doctors told you about due dates and the accuracy of the scans - like which one would be more closer the earliest or the routine 12 week one?

[Mel09]

I have always had irregular periods and needed early scans to determine gestation, and have been told by everyone that the earlier the better as they are more accurate!

It's only around a weeks difference, and that is normal...

[Je$$_84]

I have the same issue, with my first i was given 5 differing EDD dates. As i have irregular periods and my EDD couldnt be acuratley determined by charts we went by US dates. My son was supposed to be born originally in mid october. We went by the last possible date they gave me which was early november and the hospital let me go Overdue by that last date. (they were confused with EDD) once i gave birth and they check the placenta they told me bubs was actually quite overdue and i would have been around 44 weeks gestation. meaning my 12 week scan would have been accrate.

This time i was told 12 week scan was more acurate as i had MS and by about 12 weeks (i was 13 weeks 3 days at my scan my date changed from my original 7 week scan.) is when they were most acurate.

From what i've been told all EDD are never acurate, i'm just going by my 12 week scan which is 19th may, my 18 week scan showed 25th May but fundus measurements showed i was 2 weeks ahead of that. so were sticking with 19th may...

i guess the only thing EDD are good for is determining if you are too Overdue. i'd just say sick with the 12 week scan and hopefully you'll be lucky and have bubs earlier.

Good luck

[Schmickers]

During the first eight to ten weeks or so of fetal development, there are a lot of visible changes occurring as the egg develops into a growing fetus and the various organs and structures develop, so the earlier the scan, the better the chance of seeing something that gives a good idea of gestation. After this, there are less visible changes, just the size of the baby increases, and the sixe of the baby is a notoriously innacurate way of determining due dates.

However, the due "date" is really a misnomer - an astoundingly small percentage of babies are actually born on their due date. There is a four week "window" where the baby is ready to be born, and the due "date" is simply the day that falls into the middle of that period.

So, I would take your earliest ultrasound EDD, and calculate the period two weeks either side of that - that is when the baby is "due".

Some hospitals will tell you that ten days past the due date is "too overdue" and that the baby should be induced. In actual fact, research shows that there is no increase in problems up to 14 days after the due date, so don't feel pressuredinto having an induction that you probably don't need. In actual fact, you can push past the fourteen day mark if you monitor the baby and the placental function closely - even early ultrasounds are not 100% accurate, and babies who stubbornly do not come on the day or week we have chosen may well not be due as a result of an inaccurate dating scan.

[Twin Sister]

I had a few U/S as well and the earlier ones were more accurate. My doctor went by my 8 week U/S that said I was due on November 18th, even though my 20 week U/S said I was due November 6th. DS was born on November 18th

[Meluchja]

Hi,
I was told that dating scans are only accurate before week 11. I went through a similiar situation, and got very worried when I was told at 18 weeks that DS was measuring 2 weeks behind my dating scan at 7 weeks. I had to go back 2 weeks later to check measurements again, but he was back on track again, the sonographer just put it down to a growth spurt.
I would go by your first dates.