timings of 12 week scan - When is it? Really confused!

[Vickyp]

Hi all

I was just wanting to check out the timings of things as I'm really confused about what the standard way of counting how pregnant you are is. I was counting myself as being 9 weeks pregnant tomorrow - which is 7 weeks since positive test date and is how my hospital time it.
I have got the Zita West 'Natural Pregnancy' book and she seems to count it that I am 7 weeks pregnant - according to her list of weekly progressions (I am judging this by my last two scans and how big the baby is etc). Her first trimester seems to end at what I would have called week 14 but she is calling week 12 so my questions are:!!!
1. How long is a pregnancy? - Is it 40 weeks from the date of conception or ET and therefore 42 weeks from LMP or is it 38 wks from date of conception?
2. When is it 12 weeks in terms of reduced risk of miscarriage - same timing questions.
3. When is 12 week scan - would that be what I would call 12 weeks or is it 14 weeks?
Hope to hear from someone soon so I can be less befuddled! Thank you and hope everyone's doing well. Love Vicky

[Susie]

Hi, I dont know about what Zita says as I have never read her book, but as far as pregnancy goes. You are classed as 2 weeks pg on the day of ET and 4 weeks at test date. The pg lasts for 40 weeks from your last period.
The 12 week scan is done at 8 weeks after test date and this is when the miscarriage rate drops. From what you say I think you are actually 11 weeks pg, but maybe I have misunderstood what you said?!?
Good luck with the rest of your pg
Susie

[Susie]

Forgot to say if you look at the list of menus down the left hand side theres a section called resources and has a pregnancy calculator which will tell you how far gone you are, and when your due date is.

[k]

Hi Vicky

I remember I was confused at first. In a natural pregnancy they count 40 wks from LMP, because it isnt always known exactly when conception took place, although usually it is 2 wks later. Obviously with IVF, we know dates of conception. (And dont use LMP dates because our natural cycle is completely out at this stage!)I always thought you counted back 2 wks from EC day, but as Susie says I think it may be ET day? (Im sure thats how the calculator works it out on here). I would go with what your hospital says, after all they know the dates of EC and ET! Could Zita be talking about the actual age of the embryo/fetus from when it was concieved??
As far as the start of the 2nd trimester, which ever book you read will be different! Some class 12 wks as the start, some 13 wks and some 14 wks!
As far as I was concerned, because 12 wks is the time normally mentioned for when the risk of miscarriages drops, I counted this as the start of my 2nd tri. (It also took long enough to get to 12 wks, so I wasnt waiting any longer!). Hope you arent more confused now!
Take care
Love Kim

[Smita]

Hi Vicky,
just to add further to your confusion !!or maybe clarify it
The 12 week scan is usually done from between 12 weeks after your LMP date to 14 weeks after your LMP date..
They usually want to do a nuchal fold test then- to try and find out any abnormalities in the baby if there..

smita

[Vickyp]

Hi everyone and thankyou for your responses.

I am a little less confused now as you all confirm what I thought - thank you! I have looked at lots of websites (no surprises there!) that seem to count from date of conception rather than what would be our date of lmp (if we had concieved naturally) - which makes it seem a bit worrying as the measurements of how big the baby are are completely different if you are counting the other way - if you see what I mean! Sorry - all getting very difficult to explain! Anyway thank you very much for your responses. Vicky

[LittleP]

Vicky

If you look at the left hand side of the page there is a heading:

Resources

and under that heading is a sub-title:

Fertility Calendar

If you go into that you can put your dates in and then you will be told exactly how pregnant you are.

I know this is all very confusing, but my hospital said that on the date of my positive pregnancy test I was officially 4 weeks pregnant!!

Hope this helps

Little P

[Vickyp]

Hi Little P

Thankyou for responding - it's not that I don't know how pregnant I am (I am 9wks & 2 days). It's that I have been looking at LOADS of websites detailing the progress of the baby etc and a lot of them seem to count from the day of conception rather than the day of LMP. I noticed this after my second scan at 8 weeks - the baby was 8mm but I checked when I got home & found a lot of websites saying that the baby should be much bigger so I started to worry, but then found more websites saying that it should be between 8-11mm at that age which was fine obviously. (I have just had a look so I could put in a link to show you what I mean but obviously I can't find one now! Typical.) I worked out that some were counting from LMP and some from conception anyway all of this has lead me to become confused about when I can actually feel I have I passed 12 weeks (if I get that far) so I can feel less worried about miscarriages etc. Is it actually what I would count as 14 weeks - It seems from the answers of everyone here that it is 12 weeks from LMP (or in our instance two weeks before ET) - What a hugely long winded reply! How are you doing anyway?! Vicky

[LittleP]

Vicky

Why can't things be simple hey - there's so much confusion about dates isn't there?

I'm doing really well - had a lovely visit with my Midwife yesterday and heard Little One's heartbeat, also heard the baby kicking the Doppler which was really funny!! Can't wait to really feel those kicks now!!!

Hope you're feeling ok.

Little P