Fetus head up is in breech position. It is usually related to the laxity of the abdominal wall of the pregnant woman, uterine deformity or placenta uterine fundus landing, short umbilical cord, etc.. 1. Maternal abdominal wall laxity. The laxity of the abdominal wall of the pregnant woman leads to a larger space for the fetus to move in the uterine cavity, and as the pregnant woman walks, sleeps and other activities, it will affect the position of the fetus, and the position is not easy to fix, forming the breech position. 2. Uterine deformity or placenta uterine floor bed. Uterine deformity or less amniotic fluid in the uterine cavity of a pregnant woman leads to a smaller range of movement of the fetus in the uterine cavity, and the phenomenon of fetal head facing up. In addition, multiple births or fetal malformations can also result in causing the fetus to have a small range of motion within the uterine cavity, also causing the fetal head to be turned upward. If the fetal head is upward before 30 weeks of pregnancy, most of the fetus can turn to normal with fetal activities. If the fetus does not turn to normal after 30 weeks of pregnancy, it can be corrected by knee-chest position or external inversion under the guidance of the doctor. If the fetal head is always upward, cesarean section is needed.