Confused after 12 week scan

[surreygirl1987]

Hello! So I had my 12 week scan this afternoon. All went well and we are delighted. However- can anyone help me with some questions I Have?

1. My due date has been pushed back by a week!! I am pretty positive (within 2 days) of when I ovulated because I was temping, using opks etc etc etc. So which is more accurate - the one they gave me today or the one based on my cycle (which I also calculated based on my Fertility Friend app data)?

2. it seems to be measuring 38th percentile in size. But if it's on the small size for the dates... why have they changed the due date? Surely it's based on size? So why are all babies not average at 50th percentile if they go on average size = how far along?

Hope those questions make sense... thanke.to.anyone who can help explain how it all works! Didn't like to quiz the woman too much as they seemed really busy!

I had mine yesterday and my due date was also pushed back by a week. I think they're wrong and baby will have a growth spurt, if they're right it means I got a super strong positive before AF was even due ( and I know I was late!)

I don't know much about the percentiles though, I don't remember him telling us any percentile.

Oh just realised I meant they pushed my date forward not back! As in I thought I was 12 weeks but they now have me as 12+5 !

Hmm the percentile thing was on my paperwork? She didn't say anything at the time, it was just from looking at the notes afterwards that I saw that!

I've never had centiles on a dating scan? I thought the whole point was that all babies develop at roughly the same rate till about 14 weeks.
I wouldn't stress too much over due dates. The window for term is quite wide anyway (37-42 weeks). Also even if you're tracking, sperm can hang around for days and you can't really tell precisely when you ovulate. I'd probably go with the dating scan as that's how big the baby actually.measures.