Placental maturity is not related to the timing of labor, which depends mainly on when the mother initiates contractions. Placental maturity refers to the degree of maturity of the placenta. Placental maturity level 1 marks immature placenta, level 2 late marks partially mature placenta and level 3 fully mature placenta. As the placenta is fully mature at grade 3, the placenta may have decreased function and therefore the ability to transport oxygen and nutrients, which can be dangerous to the fetus, and the mother may be in labor at any time, so she must go to the regular hospital obstetrics department in time. In addition, because the placental maturity classification is a subjective decision made by the ultrasonographer based on the ultrasound image characteristics of the placenta, it is not possible to accurately determine whether the fetus is mature or not, and it needs to be combined with other clinical indicators such as gestational week and amniotic fluid for a comprehensive analysis.