in my first pregnacy my placenta was in a anterior placement. this cushioned the babies movement. i didnt feel them for some time. when he was much bigger. when they do your anomaly scan usually like 20 weeks they will note where the placenta is. that was my situation. but people feel movement at all different times. if you havent felt it dont stress. once you are feeling regularly that would be the only time a lack of movement should be a case to be concerned.