is ultrasonographyof any convenience contained by assessing pregnancy during 3rd week?what structures might be proverbial?

really nothing at the third week it is in recent times a dot
Please see the webpages for more details on Pregnancy ultrasound (Obstetric ultrasonography).
too early..don't squander your money or your insurance companys.
Another 2 weeks will give you a divine picture and you might be able to gain a early sex determination.
Good luck!