Aim. Conduct an index assessment of the periodontal condition and determine the pathogenetic significance of osteotropic mediator changes in the oral fluid in pregnant women with vitamin D deficiency. Materials and methods. In 42 pregnant women with vitamin D deficiency (a decrease in venous blood is less than 30 ng/ml) and in 31 pregnant women with a normal vitamin D content (30—100 ng/ml), the parodontological status was assessed by determining the Hyperin Hypericum Index value, the papillary-marginal alveolar index, and the periodontal index. In the oral fluid, the concentration of osteoprotegerin and the ligand of the soluble activator of the kappa B nucleation factor (sRANKL) were determined by immunoenzymatic analysis. Conduct a comparative analysis of the antimicrobial and cytokine profile of the oral and gingival fluid in pregnant women with chronic generalized periodontitis for varying degrees of severity. Results. It was found that in pregnant women with vitamin D deficiency, periodontal pathology was more frequent (p=0.008) compared with pregnant women with normal vitamin D content in blood (67% vs. 17%). In oral fluid in pregnant women with vitamin D deficiency, the content of osteoprotegerin decreased along with an increase in the sRANKL/osteoprotegerin ratio, which promoted the activation of osteoresorptive processes in the alveolar bone. Decreased osteoprotegerin in the oral fluid in pregnant women with vitamin D deficiency was accompanied by an increase in cathelicidin LL-37 in the development of inflammatory periodontal diseases, which promoted the activation of antimicrobial congenital mechanisms in the oral cavity. Conclusion. With vitamin D deficiency, pregnant women activate mechanisms that enhance osteoresorptive of the alveolar bone, change the activity of congenital antimicrobial mechanisms in the oral cavity, which contributes to the development of inflammatory periodontal diseases during the gestational period.