Third trimester ultrasound??

Just curious if any of you are not having one? My last u/s was at 22 weeks (I'm 28 now) and everything came back good. This was a follow up u/s to my 20 week one since they spotted a focus in the abdomen that they wanted to get a better look at it and better picture of nose and mouth. Everything appeared to be okay in that one. 
At my midwife appt yestersay she said that another u/s is not necessary unless their is area of concern about something. Is this the norm? I thought for sure I would have one more before baby is born. 
Thanks ladies!