I ask because I wanted the nuchal scan but my appointment's not until I'll be 13+4 - which seems cutting it a bit fine if I'm a couple of days out (and at a previous scan I was 2-3 days further on than they first thought).
So are most people pretty accurately what they thought they'd be at their 12 week scan, or does it change a lot? Just trying to get a sense of how likely it is that they'll be able to do the nuchal...