Being plus-sized does not affect the scan in any way, as the visuals will still present correct measurements. However, in some cases, it might be more difficult to hear the heartbeat clearly. What may add to the difficulty of hearing a heartbeat early in pregnancy is a tipped uterus which sits more to the back and rests on the bladder. Follow-up scans will reveal a more prominent heartbeat as the uterus shifts into the correct position.