Cervical cerclage at 12 weeks with the lower edge of the placenta covering the endocervical os is not recommended because of the risk of puncturing the placenta, causing vaginal bleeding and aggravating the condition. Cervical cerclage is mainly applicable to pregnant women with cervical insufficiency, and is usually considered at 12 weeks of pregnancy; the procedure is also applicable to patients with frequent miscarriages and loosening of the uterine opening, which can effectively prevent preterm labor; however, cervical cerclage should not be performed if the lower edge of the placenta is covering the endocervical opening, because the operation is very likely to pierce the blood vessels of the placenta, which can cause vaginal bleeding and even miscarriage. For 12 weeks the lower edge of the placenta covers the opening of the cervix, that is, the placenta is low status, it is recommended that conservative treatment, follow-up observation; it is recommended that pregnant women bed rest, prohibit sex, elevate the buttocks, try to make the placenta upward long, if there is bleeding or other discomforts in a timely manner to consult a doctor, do not blindly do the cervical cerclage.