You usually need a full bladder and will very likely be TA. They may tell you to empty your bladder at the scan anyway though !
Unless you’re unlucky like me..
I had to have so many TV scans this last pregnancy because I have a very tilted uterus. Even at my 20 week scan they wanted to do TV for a better view of everything. And then I continued to need more TV scans later on during growth scans to check where my placenta was as it was low lying.
I don’t know about other hospitals but towards the end of my pregnancy because I was under consultant I’d go there for my scan and sometimes have to sit and wait 2 hours for my consultant appointment 🥲
At my last scan for the pregnancy I had csection preop, scan and consultant appointment all the same day but with around 2 hours between each

but because I’d also been admitted to the ward for bleeding I could just go back to my room between appointments