If a miscarriage occurs at 26 weeks of pregnancy, the majority of cases are considered to be related to cervical insufficiency. Because the fetus is relatively well developed by this month, miscarriage due to abnormal fetal development is not common. However, in the case of cervical insufficiency, in the middle of pregnancy, the further enlargement of the uterus will lead to relaxation of the cervical opening, which will cause miscarriage. Therefore, it is advisable to go to a gynecological clinic for a cervical function test after recovery for this type of miscarriage in the first trimester. If the 8.5 dilation stick can easily pass through the cervical opening, it is considered that there is cervical insufficiency. These patients need to consider an early cervical cerclage during their next pregnancy.