There is no exact number to determine the chances of preterm labor with complete placenta previa.
The risk of preterm labor is determined by the presence of vaginal bleeding and the presence of placental implantation.
Generally speaking, if there are no other abnormalities associated with a complete placenta previa, a small percentage of pregnant women may be able to carry their pregnancy to full term without preterm labor.
If the complete placenta praevia is accompanied by vaginal bleeding and placenta implantation, then it is necessary to seek timely medical treatment, first keep the baby on birth control treatment, and according to the development of the fetus, it is usually early labor.
Therefore, whether or not complete placenta previa will lead to preterm delivery has to be determined in conjunction with other relevant factors, and cannot be generalized.