Aim: To determine the value of biochemical markers of isthmic-cervical insufficiency in patients with a shortened cervix for predicting premature birth. Design: А prospective study. Materials and methods. In the second trimester of pregnancy, 100 pregnant women with a high risk of isthmic-cervical insufficiency were examined three times in dynamics (at 12–14, 18–20 and 26–28 weeks). The division into groups was carried out retrospectively taking into account the length of the cervix according to the results of ultrasound cervicometry: Group 1 — 32 patients with a conditionally normal cervical length (26–30 mm), group 2 — 39 patients with a cervical length of 20–25 mm, group 3 — 29 women with a cervical length of less than 20 mm. In each group, the course and outcome of pregnancy were analyzed, and the levels of specific biochemical markers in the blood serum were studied: matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9) and serum fibronectin (FN). Results. Concentrations of MMP-2 and MMP-9 are significantly higher in pregnant women of the 2nd and 3rd groups. A significant increase in their levels was noted during the study. The level of serum FN was initially increased in the 2nd and especially in the 3rd group, but decreased during surgical correction. When performing cervicometry, in addition to shortening of the cervix, the most significant ultrasound signs of infection were noted — a sludge phenomenon (accumulation of dense echopositive sediment located near the lower pole of the fetal bladder at the inner throat of the cervix) and suspension in amniotic fluid. Conclusion. Measuring the length of the cervix in combination with the study of the levels of MMP-2, MMP-9 and serum FN, as well as the detection of signs of infection of the urogenital tract will contribute to the timely implementation of preventive measures and a differentiated approach to the choice of tactics for the management of pregnant women with shortening of the cervix. Keywords: shortened cervix, isthmic-cervical insufficiency, collagenogenesis, premature birth, cervicometry.