How many weeks for the third cesarean section does not have an accurate time, it needs to be combined with the physical fitness of the pregnant woman, the condition of the fetus and the results of the pregnancy test to make a comprehensive judgment, and generally can be carried out in the 38th-39th week of pregnancy cesarean section. However, if there are abnormalities, it can be appropriately advanced to before 37 weeks. If the pregnant woman has already had two cesarean sections, the elasticity of the uterine scar is relatively poor, and spontaneous rupture is likely to occur. Therefore, in the middle or late pregnancy, it is necessary to choose to carry out a cesarean section in a timely manner according to the condition of the uterine scar. If the pregnant woman and the fetus are in good health and the test results are normal, a cesarean section can usually be performed in the 38th-39th week. However, if the test results are abnormal and the pregnancy is weak, then an early termination of the pregnancy can be considered, with a C-section performed before about 37 weeks to avoid accidents. However, no matter when you choose to have a cesarean section, try to have it when the fetus is already mature, and you should pay attention to go to the hospital for regular checkups in your spare time to avoid any impact on the health of the fetus.