It actually depends on your insurance and your doctor
I am 29 weeks and 2 days and I do not get to get anymore.
Im 36+3 and havent got another one form my doctor since 20 weeks. I paid for a 3d at 29 weeks. But yes it depends on your insurance and doctor.
They actually have to do one more to know if the baby is breech and to know the weight
Atleast they do in Florida
Many drs don't do any after 20 weeks unless there is an issue or you are considered high risk. They can tell how the baby is positioned by feeling your belly, they don't need an ultrasound for that.
It depends on your doctor and insurance, some people don't get any more ultrasounds after the 20 something week one to find out the sex