Well my 20 week scan was probably 20-30 minutes long. The tech looked over everything at first, and than went back over and explained what different body parts etc. were (although for the most part it was pretty easy to tell). She also checked the sex of the baby (several times for me). I had scheduled an OB appointment directly afterwards, mostly because I wanted to get it done in one day. I believe that in the majority of the cases everything is absolutely fine, I'm sure you have nothing to worry about
