To prevent the recurrent spontaneous miscarriage caused by incompetent cervix, Fenglin Chen, president of Beijing Antai Hospital, made the treatment for incompetent cervix improved by use a kind of biotic hoop instead of the stitch (or cerclage). Practices prove that the carrying capacity of the biotic hoop is stronger than the stitch. The success rate of preventing miscarriage is 100%. Traditionally, the procedure of cervical stitch placement means to place a stitch (or cerclage) into the cervix to tighten and close it. The shortage of this method is that the bearing capacity of the stitch is sometimes not strong enough to carry the pregnancy and maybe, the stitch can roll down the cervix and loosen.

Incompetent cervix is a condition where the cervix dilates prematurely without detectable contractions. Technically speaking, a cervix is classified as incompetent if it fails to maintain an intrauterine pregnancy to term. The cervix begins to dilate far too early and easily, the amniotic membranes or blood loss, the patient go into a rapid, short premature delivery. To diagnose incompetent cervix, one should take some examinations including: transvaginal ultrasound, medical history, combination of hesterography and hesteroscopy, cervix dilating test, (medical history is most important, and an internal examination; hysterograpy, described in the previous section; transvaginal ultrasound is to learn the suspected abnormalities of the cervix; cervix dilating test means to pass a dilator through the cervix into the uterine cavity, if a size 6 hegar dilator passed, it can be confirmed as incompetent cervix .)