Professor Chenfenglin pointed out: traditional cervix is how to do? The traditional cervix ring is to tie the mouth of the palace with silk thread around 20 weeks of pregnancy. The defect is that the incision is only external. Once the contractions are started, they can not effectively prevent the expansion of the cervix, and they can easily induce contractions and miscarriages. It is also easy to cause cervix infection. Causes the fetal membrane to break early miscarriages, the success rate is less than 20 %.