Modern understanding of the role of vitamin D in the genesis of premature birth (literature review)

Preterm births remain one of the most pressing challenges in modern obstetrics, accounting for approximately 70% of perinatal mortality cases among preterm infants. Even those who survive face an increased risk of chronic lung diseases, hearing and vision impairments, and cognitive dysfunctions. The pathophysiology of preterm births is complex and remains insufficiently understood. One of the potential factors influencing preterm birth is maternal vitamin D levels during pregnancy. According to biological assumptions, adequate levels of vitamin D may reduce the risk of preterm births due to its immunomodulatory properties. However, large-scale, well-designed randomized studies are needed to confirm this and to elucidate the mechanisms of vitamin D action. Aim - to assess the relationship between maternal vitamin D levels during pregnancy and the risk of preterm birth. The analysis involved a search of scientific publications in databases such as "PubMed," "Google Scholar," "PMC," "Web of Science," and other reputable sources. The review included randomized controlled trials, cohort studies, case-control studies, and review articles. Key search terms included: "preterm birth," "vitamin D," "immunomodulation," and "vitamin D and immune system". Evidence suggests that vitamin D plays a role in regulating the innate and adaptive immune systems. Both "sterile" and "infectious" inflammation are triggers of preterm births, and low levels of vitamin D may exacerbate these processes. Specifically, studies have shown that higher doses of vitamin D reduce the risk of preterm births. Conclusions. Current research highlights the role of vitamin D in regulating immune functions in reproductive tissues and its impact on pregnancy outcomes. However, the existing evidence is insufficient to determine the optimal vitamin D levels required for positive immune modulation. Additional well-designed clinical studies are needed to establish a causal relationship between vitamin D deficiency, immune system modulation, and improved reproductive outcomes through vitamin D supplementation. The authors declare no conflict of interest.