Maturity grading usually refers to the maturity of the placenta. Clinically, the maturity of the placenta can also be indirectly determined by ultrasound by classifying the placenta into grades 0-3 based on the changes in the images of the placental basal plate, the chorionic plate, and the placental parenchyma. The placenta usually forms at 12 weeks of gestation and reaches level 1 around 30 weeks of gestation. After the full term of pregnancy, most placentas will reach grade 2, and if a cesarean section is chosen, placental maturity needs to be observed. Try to wait for the placenta to mature at the late stage of grade 2 before performing the operation. If the due date is exceeded, most of the placentas will reach grade 3, and there is the phenomenon of aging of the placenta, and the fetal movement needs to be monitored to prevent fetal distress and hypoxia. At 33 weeks of pregnancy, the fetus has basically matured. At this time, pregnant women have difficulty in moving around, so they have to pay extra attention to safety, monitor the fetal movement, and consult a doctor immediately if they feel unwell.