Can I just say its not fair! I started wearing maternity clothes at 10 weeks! lol I will be 28 weeks on Monday so you can guess how big I am now lol
As for the scans, 4d scans are done by qualified sonographers but are intended for bonding purposes and should not replace your usual ante natal scans. My guess would be, as has been mentioned, she simply wasnt measuring the right size for the amount of weeks she is so having a scan as a precaution. If there was any real worry, she would have been sent straight up to the hospital. Measuring the tummy at ante natal appointments is only a guideline and not everyone grows at the same rate so hopefully your friend isnt worrying too much (easier said than done I know as Im a natural worrier too!)
Congrats on expecting a little boy mountainboo, Im having another girl!