It is safer and normal for the lower edge of the placenta to be at least 3cm from the endocervical opening at 24 weeks. The placenta is an important fetal appendage, and its position, size and relationship to the endocervical opening determines the risk of a woman’s pregnancy. Normally the lower edge of the placenta should be some distance from the endocervical os. If it is closer to the endocervical os, it can cause symptoms such as painless vaginal bleeding, which is known as placenta praevia or placenta previa. If it is too close to the endocervical opening, it can easily cause vaginal bleeding during pregnancy, and in severe cases, it can lead to miscarriage. It is usually safer for the placenta to be at least 3cm from the cervical opening at 24 weeks. If a pregnant woman finds that the placenta is too low during a pregnancy test, she should seek medical attention. During pregnancy, pay attention to rest more, at the same time, should relax, avoid tension, anxiety, any discomfort should be timely to the hospital, the doctor to clarify the diagnosis, and cooperate with the doctor to deal with the symptoms.