Baby not changing positions.

Sino po sa mga nkpag paultrasound na or nagka baby na yung naka experience na hindi nagcchange ng position si baby? I mean from your previous ultrasound to the current same lang ang position. 15 weeks and 17 weeks nag paultrasound ako and concerned lang ksi hnd sya gumagalaw/nagcchange positions. Normal lang ba to mga mommy? May heartbeat naman sya at consistent sa 143bpm.