Background <p>The primary treatment for cervical insufficiency is cervical cerclage (mechanical support) with vaginal progesterone (biochemical support). Cerclage is a surgical procedure that mechanically increases the tensile capacity of the cervix. Therefore, it is necessary to analyse the effects of cerclage from a mechanical point of view.</p> Purpose <p>To analyse cerclage techniques based on physical principles and mechanical forces.</p> Methods <p>We assumed that the cervix is a thin-walled pressure vessel and applied a uniform vertical distribution model, a linear vertical model, and a non-linear vertical distribution model.</p> Results <p>According to our model analysis, the higher the position of the thread, the thicker the thread used, and the greater the number of threads, the more effective the confining force on the suture, when performing a cerclage.</p> Conclusion <p>It is necessary to provide an appropriate cerclage for each patient based on these mechanical characteristics, in addition to considering the risks and benefits and biochemical interactions of the cerclage.</p>