12 & 20 week scans - same EDD??

[adamskatie]

Hi Everyone,

I've got my 20 week scan in 2 weeks and just wondered if they date you again in this one as they did in the 12 week one???

If so, does your EDD remain the same or change again slightly?

This is my first pregnancy and have already been given 2 different dates (only out by 2 days) so was just wondering if it would likely change again!!??

What has been past experiences?

Thanks in advance x

 

[lousielou]

I've not had my first scan yet, but when I was pregnant with my son, the EDD they gave me at my first scan was the one the medical staff went by from then on. It wasn't altered at all. The 'official scan EDD' was two days earlier my EDD based on my LMP. When I got very overdue, I mentioned the fact that my LMP EDD was later, but my MW was having none of it... In fact, it even said on my maternity notes 'NT scan EDD final'.

I think that in early pregnancy, dating scans can be very accurate, but later on not so much - that's why they take the measurements at 12/13 weeks

xx

 

[MummyToAmberx]

Id go by date given at 12wk scan! Also date given at 12wk scan is your EDD, if you get different date at 20wk scan unlikely they will change your notes EDD

2nd pregnancy i got same date, 8,13,16,19 weeks.

1st pregnancy i got 30th @ 18+6 , 22wk i got 27th. She came on 31st lol so earlier 1 was the better one.

 

[Jox]

hi, they dont date you again at your 20 weeks scan. your 12 weeks scan is called your dating scan as this is when they date your pregnancy and give you your EDD. they wont change it later on.

xxx

 

[lynzlogan]

same here no change at DS's 22week scan. that was just for gender and measurements!

With DS Lmp dated EDD was 30th july...12wk scan EDD was august 5th...Leo arrived on july 29th so i prefer LMP's!

 

[MissFox]

Usually the scan if you get it at 8 weeks is within 5 days accurate (babies grow at different rates) and by 12 weeks it should be within a week accurate.

 

[Mrs_N]

dating is only accurate up until about 13 weeks as after that babies grow at different weights.
they shouldn't try to date at your 20 week scan, although I have heard of it.

 

[angelstardust]

8-13weeks is the optimum time for dating the EDD.

Before 8 weeks, the babies grow at different rates, after 13 weeks again they grow at different rates.

If your 20week scan puts your dates out by 6 or more days, then they may leave it to the judgement of the consultant who will usually then look at your LMP date (if you are sure of your LMP) and make a decision based on that.

Hopefully, you will have a problem free pregnancy and go into natural labour and your EDD won't be needed for anything important (such as inductions or the need for steroids if baby is coming early).