Firstly.. Congrats on your pregnancy... Secondly.. I am 31 weeks,3days, and I have had 3 total. One a t 14 weeks 3days, one at 19 weeks 4 days, and one at 30weeks 3days ... The first was to check dates, the second was for all the measuaring and the last one was just becuz the Dr. Wanted it done, and I was there,.. Haha... So it really depends on the Dr.
Umm I wouldn't nessarly "bend the truth" about the twins, but you can express your concerns or maybe "bend the truth" about when you think your last perios was....
Unless you have already gone, and they have to recorded, but if not, then you might beable to get away with that, also if you ever have a single problem, go to the er, and they would probably do one there... But only go if you are really having a problem... But also at this early in your pregnancy, an u/s isn't going to show much more than what looks like a bean or a cashew nut...Lol....
Either way good luck~