How many ultrasounds do you get during pregnancy?

Normally only two, right? One at 6-10 weeks and another 20 weeks. But how would they know if your amniotic fluids low and stuff? That’s just a big concern of mine. Or how big your baby’s getting?

Like my baby measured a week ahead at my 20 week and my uterus is measuring ahead too so I dont wanna go through labor and try to push my baby out just for him to be too big and need a c section.