My ultrasound result shows placenta previa totalis at 12weeks, will it move away from the chix as pregnancy progresses?

Usually : The placenta doesn't actually move but the uterus grows and pulls it away. Most previas present that early will resolve

Yes, possible: Previa: Placenta overlies the cervix/birth canal. Gr 1 means placenta is close, Gr 4 means it's directly overlying/blocking the baby's exit -- high chance of preterm labor & bleeding; you'd need a C/S at 36-37wks. More common in woman w/ hx of C/S & smoking. Not much you can do but wait. If dx'ed early, the uterus still grows/stretches and a placenta can migrate away even in 3rd tri. Follow w/ US.