Generally speaking, the distance from the lower edge of the placenta to the endocervical os is greater than 2 cm, which is considered normal in clinical practice. If the distance from the lower edge of the placenta to the endocervical os is less than 2cm, the placenta may be hypoplastic or placenta previa. The placenta may be in a low position due to factors such as previous damage to the endometrium during formation. Low placenta position is usually not diagnosed in the early stages because it moves up as the fetus grows. After 28 weeks of pregnancy, if the lower edge of the placenta is still less than 2cm from the endocervical opening, the patient and his/her attending physician need to be informed and treated promptly. Pregnant women with low placenta position or placenta praevia have an increased chance of bleeding in late pregnancy, so they should pay attention to their own condition during pregnancy and go to the hospital for timely treatment if there is any discomfort.