Good evening, the doctor told me to come at 37 weeks for an appointmen…

Good evening, the doctor told me to come at 37 weeks for an appointment and we'll see the baby's weight and I'll decide on my own if I'm going to give birth naturally or with a cesarean section. Now it's the end of week 38, I don't plan to have an ultrasound. ? Decided when contractions will start then I'll go to give birth. I wanted to clarify about the time of contractions in the maternity ward, can they determine if I can give birth naturally or should I get checked out by an ultrasound?