I had to drink water beforehand. I didn't have to take any clothes off because they just did the scan externally. I just lay down and pulled my skirt down a little bit. They measured the nuchal fold plus all the bones and checked the baby's brain etc.

I've also had that you can tell the baby's sex around this time but it's not something they'd do (as far as I'm aware). This happens at the morphology scan (around 20 weeks).