Relevance. One of the causes of perinatal morbidity and mortality, the growth of child disability is extremely early and early premature birth (PB), which is most often associated with cervical insufficiency (CI). One of the etiological factors of CI development is the insufficiency of connective tissue (CT), as well as deficiency of vitamins and micronutrients included in its composition. The leading role in the regulation of CT metabolism belongs to vitamin D. Its deficiency leads to a number of complications during pregnancy – preeclampsia, gestational diabetes and vaginal biocenosis violations.

Aim of research. To determine the effect of vitamin D on vaginal biocenosis in pregnant women with cervical insufficiency.

Materials and Methods. 27 women in the term 22-32 weeks of pregnancy were examined and divided into the main (16 pregnant women with CI) and control (11 pregnant women with physiological pregnancy) groups. The content of Total vitamin D in blood serum was determined using ELISA. The condition of vaginal biocenosis was determined according to the results of Femoflor 16 and bacteriological studies.

Research result. The results indicate a significant decrease of the vitamin D content in the serum of pregnant women of the main group (17,26±1,4 ng/ml), which is 13,7% lower than the physiological norm and 38,0% than the indicator in pregnant women of the control group (28,04±1,6 ng/ml; р < 0,05).

The average value of vaginal pH in main group of pregnant women was 4,7 in 68,0% cases. Pathological changes in the vaginal microbiocenosis were represented by bacterial vaginosis (31,3%), aerobic vaginitis (43,8%) and candidosis (56,3%). In the spectrum of the isolated microflora Gardnerela vaginalis (25,0%) and Atopobium vaginaе (12,5%) in association with Mobiluncus and aerobic microorganisms (S. Faecalis, E. coli, Klebsiella spp.) were dominated. 68.8% women of main group had a decrease lactobacilli (lg 3.4 CFU/ml).

Conclusion. Pregnant women with cervical insufficiency are characterized by a significant deficiency of vitamin D in combination with pathological vaginal biocenosis, which aggravates the course of pregnancy and contributes to the manifestation of premature birth.