A gestational sac 1.3cm below the incision at 9 weeks of pregnancy suggests that the gestational sac is closer to the previous cesarean section scar in the early stages of pregnancy. As the pregnancy develops and the uterus enlarges, it is possible for the gestational sac to grow upwards in the later stages, but if the gestational sac continues to migrate downwards it may form a keloidal pregnancy, which needs to be dealt with under the guidance of the doctor.
If the gestational sac continues to grow upward, it may develop into a normal intrauterine pregnancy, to full-term delivery, you should do a good job of regular obstetric examination, review obstetric ultrasound, timely understanding of the position of the fetus and placenta.
If the gestational sac continues to migrate and grow downward due to various reasons such as endothelial malnutrition, it may develop into a scarred pregnancy. Scarred pregnancy is an abnormal pregnancy, due to the thin wall of the uterus at the scar, in severe cases, uterine rupture may occur, which is a more dangerous situation and requires prompt medical attention.