Can placenta prevera lead to a preterm birth?

It can. Placenta previa means that the placenta is blocking to cervix, which is the opening from the uterus to the vagina. If the cervix starts to open, heavy bleeding can occur, making it necessary to deliver early to protect mom's health. To reduce the risk of life-threatening bleeding, doctors may deliver early.
Yes. If preterm labor begins & the placenta tears because of its odd location the resulting bleeding may require an urgent delivery. There are more than one form of previa. A simple form just has the placenta on the wall near the outlet. A complete previa has it totally covering the outlet. If no preterm labor occurs, you may carry to term, but surgical delivery is pretty standard.