Why didn’t my doctor tell me this .....

So today at 30 weeks pregnant I had an elective 3d ultrasound to get some cute pictures of baby , and the tech mentions I have an anterior placenta . Suddenly it all makes sense , why hubby has trouble feeling her kick , why at 30 weeks her kicks are still pretty faint most of the time for me , and why sometimes I struggle to do my kick counts . Why would my doctor not mention this before????? I’m kind of annoyed . Not life changing just would of been nice to know . I’ve had several other ultrasounds with my normal doctors office