Date of conception confusion

[Coco899]

Hey guys. I just wondered if anyone else had the same confusion over dates...

I know they aren't 100% accurate but I had a scan yesterday and they put me at exactly 12 weeks, but 12 weeks ago I was on my period. Is it possible that they're out by a week and a half?
I think I was ovulating just after my period (my periods are every 3 weeks). So I think I'm about 10 and a half weeks. She was convinced it's 12 weeks exactly but that can't be right?

Is it normal to be out by a week and a half?

Thanks!

Yes it’s normal! They will go off scan dates regardless of cycle maths. I wouldn’t give it another thought to be honest as babies grow at different speeds. At your 20 week scan, your baby might measure bang on 20 weeks. Might be bigger or smaller. That’s just the way it is

Your pregnancy is dated from the first day of your last period anyway so you are counted as pregnant before you actually conceive.

@Accidentallydeletedoopsss

Yes it’s normal! They will go off scan dates regardless of cycle maths. I wouldn’t give it another thought to be honest as babies grow at different speeds. At your 20 week scan, your baby might measure bang on 20 weeks. Might be bigger or smaller. That’s just the way it is

Thank you! I thought it was but then have been reading that they're usually only 2-5 days out and not 10 days. But makes sense now. Baby must just be growing quickly!

@dementedpixie

Your pregnancy is dated from the first day of your last period anyway so you are counted as pregnant before you actually conceive.

Yes this baffles me! But once you go for a scan they throw that date out of the window and go with the measurements instead.

Yes but the dating with measurements still includes the first two weeks of the cycle- before you conceived. So if 12 weeks ago you were just starting your period , measuring 12 weeks is exactly right.
I have been dated 12+3 . The first day of my last period was the 19th February. I ovulated around 5th March.

@Bizawit

Yes but the dating with measurements still includes the first two weeks of the cycle- before you conceived. So if 12 weeks ago you were just starting your period , measuring 12 weeks is exactly right. I have been dated 12+3 . The first day of my last period was the 19th February. I ovulated around 5th March.

Ok this explains a lot 😂 thank you. I've been so confused but that makes sense now then. So it is the original date I thought!

Incase anyone is wondering why I'm so obsessed with dates - there is a reason but this has cleared it up now. Thank you!