The 24th week of pregnancy is 2 weeks small, and the first level of the placenta belongs to the tendency to maturity, which is considered to be related to the high amount of calcium supplementation, gestational diabetes mellitus, high blood pressure and other factors. The correlation between placental maturity and fetal lung maturity is clinically categorized into four grades of placental maturity: grade 0 is immature, which is mostly seen in the middle trimester; grade 1 is beginning to mature, which is mostly seen in the 29-36th week of pregnancy. If the 24th week of pregnancy is 2 weeks too small, the placenta should be grade 0. The first grade of placenta may be due to excessive calcium supplementation, or the pregnant woman is suffering from gestational diabetes mellitus, hypertension, etc., which results in ischemia and hypoxia of the placenta and causes the placenta to show aging and calcification points. If the placenta is small for 2 weeks out of 24 weeks of pregnancy, the cause of the placenta level 1 needs to be clarified, and if it is caused by a disease, it needs to be diagnosed and treated in time, so as to avoid causing harm to the fetus.