R.I. SHARIPOVA, M.E. ZHELEZOVA, D.B. SHAKIRZYANOVA  Kazan (Volga Region) Federal University, Kazan   Contact details: Sharipova R.I. — PhD (Medicine), Associate Professor, Department of Obstetrics and Gynecology Address: 74 Karl Marks St., 420012 Kazan, Russian Federation, tel.: +7 (843) 236-34-51, e-mail: rezedusha@mail.ru  The problem of cervical insufficiency continues to be relevant in modern obstetrics, as prevention of preterm […]