Thank you for your query.
More than 90 % cases of placenta previa
move upwards by the third trimester.
However, complete placenta previa has lesser chance of migrating upwards as it is lying completely in the lower segment, and completely covering the cervix
With a previous D and C, chances of adherent placenta also increase.
However, you can take precautions such as rest / avoidance of sexual activity / strain / jerky travelling etc.
Continue to be hopeful and have regular scans for localizing the placenta.
complete placenta previa requires a Cesarean delivery if it persists at term.