it depends on your doctor, your insurance, and if you start out having problems or previous problems from pregnancies. With my daughter, I had only one. With my son I had them every two weeks, to make sure he didn't need to be born earlier then he was due to one kidney working and the other now, and fluid build up in him! This pregnancy I had one in the er at 7 weeks, due to what I thought was a possible m/c, and then at 13 weeks because I was bleeding and cramping, and i'll have one at 18 weeks, and thats it. Unless there is a problem with the baby!
after my second MC , i had one US at 6 weeks, another at 8 weeks, my downs syndrome ultrasound at 12 weeks and then the big ultrasound at 18 weeks
I had one at 12 weeks but that was to check dates, and found a miscarriage. My bff had her first u/s at like 11 or 12 weeks and has had 2 others since and is only 22 weeks. I would always want more than less. Tell her you want one done sooner!
You can tell your ob/gyn that you want to have an ultrasound and tell her it's for your own peace of mind. If they tell you no, tell them yes you can. The only thing is that you might have to pay more out of pocket costs for them. See with me, I had an ultrasound at 11 weeks and then another one at 22 weeks and that was supposed to be it, but I started bleeding around 28 weeks and they did a quick one and when I started bleeding again at 35 weeks I requested another one. Since the last two were not part of the normal prenatal care, I had to pay more and my insurance paid less. I'm not sure how your insurance works, but just tell your doctor that you need to see and hear your baby and that you'll pay the extra cost. Don't let them tell you no. It's your baby not theirs and they work for you. Be stern and they'll cooperate.