Conception confusion

[Missy160194]

Hi everyone. Im new here & not sure this is the right place so forgive me if i am wrong. Looking for some advice on my 1st pregnancy.

I have always had irregular periods so unsure when i conceived. My last period started on 7th of september and finished 15 days later. I had a ultrasound and an imternal scan on october 22nd to check for pcos and nothing was found. On 30th of october found out i was pregnant, clear blue said 3 weeks + i had a scan on 7th of December which dated me at 10 weeks and 1 day. I have read about not being pregnant in 1st 2 weeks is this still the same when using the scan instead of lmp? So i would have actually conceived 8 weeks ago roughly, am i right?

[Junosmum]

Yes, you are correct.

[Missy160194]

Thank you. So why is it the baby measures at 10 weeks if it didnt actually exist 10 weeks ago lol

[Oysterbabe]

Because that's just how they do it. I don't understand why. If you are 10 weeks pregnant you conceived 8 weeks ago.

[Kaytee1987]

They add on 2 weeks so that everyone is using the same way of determining dating, otherwise it would get very confusing.