Next ultrasound?

I had an ultrasound last week at 8 weeks and everything looked good. My next appointment is at 12 weeks but I don’t think an ultrasound is scheduled... though I may call and ask.

So my question- I had a missed miscarriage in January (no symptoms, no cramping or bleeding, just no growth or heartbeat on ultrasound over two weeks). I never miscarried on my own (despite waiting almost 3 weeks) and ended up taking misoprostal and then having a d&c.;

I suddenly am wondering: how do the doctors know that isn’t happening again if they aren’t doing an ultrasound? Am I missing something? What do they typically do at a 12 week appointment that checks if the baby is still growing if they don’t have an ultrasound scheduled?