Anatomy Scan

Just had my anatomy scan this morning 18 weeks and everything seemed to look great. Baby was completely face down hugging the placenta and not wanting to move much so the tech was having a hard time getting a complete picture of the heart. My doctor said to just schedule another ultrasound for my next regular checkup in 4 weeks and that not for one second is he concerned just bad positioning. Has this happened to anyone? & if they noticed something wrong they normally would say I hope? We got no good pictures or anything because she was not cooperating. :)