As with all things not fully understood or explainable u/s should be used with caution. Do I think they are over used...yeah, I didn't need a "dating scan" I knew when all of my babies were due, but I was asked to get them, for my Dr, for my records etc. Most wm then have the 19/20 wk to check the sex or just to check on bub. A few it seems is the norm but some wm do have on eevery Ob visit and many are told they have to have to have size chacks for the last 4 wks etc. I feel that unless there is concern or medical reasons then u/s should be used sparingly, yes a lot of ppl can say the u/s picked up something that needed immediate neonatal treatment but if it was found in 5 yrs that u/s caused some weird anomaly and no Ob wanted to perform one we'd all be left scratching our heads...One of those damned if you do, damned if you don't things perhaps???