Appt at 15weeks

Annelise • 24. Married. I have a 2 year old and 1 year old sons.
So I have had 2 appts already. One in September confirming my pregnancy. One in October to do blood work an hear the heart beat. But now I have an appt next week an I'm not sure what to expect. I've had everything done in the last 2 appts an I don't find out the gender until my appt in December. So does anyone have an idea what to expect? Is it just hearing the heart beat and that's it??