Why dint they let you hear the baby's heart beat with ultrasound?

Jenn

When I was pregnant in 2014 with my now 7yo, I heard his heartbeat at every ultrasound. This time around, i was told they can't let me hear the heartbeat at my scan at 8w4d and even at my scan at 13w2d. Why don't they let you hear and see the heartbeat anymore?