Abstract
Background. Vitamin D regulates calcium–phosphorus metabolism, which is critically important during pregnancy. Its deficiency is associated with preeclampsia, fetal growth restriction, gestational diabetes, and placentation disorders. Given the high prevalence of hypovitaminosis D, particularly in Ukraine, investigation of its impact on mineral homeostasis remains highly relevant. Aim: to investigate the characteristics of calcium-phosphorus metabolism in pregnant rats with different vitamin D statuses. Materials and methods. The study was conducted on 22 pregnant Wistar albino rats, divided into three groups: hypovitaminosis D (diet devoid of cholecalciferol), correction group (vitamin D deficiency before pregnancy, followed by oral administration of vitamin D at 400 IU/kg/day from gestation day 1), and control group (balanced diet with adequate vitamin D content). Serum concentrations of 25-hydroxyvitamin D [25(OH)D], ionized calcium (Ca²+), phosphorus (P), parathyroid hormone (PTH), and alkaline phosphatase (ALP) activity were measured using standard biochemical methods. Statistical analysis was performed using MedStat v.5.2 and EZR v.3.4.1 software, with p<0.05 considered statistically significant. Results. In the hypovitaminosis D group, a significant decrease in 25(OH)D₃, Ca2+, and P was observed, accompanied by an increase in PTH and ALP activity, indicating secondary hyperparathyroidism and enhanced osteolysis. Cholecalciferol supplementation increased 25(OH)D levels, normalized calcium–phosphorus metabolism, and reduced PTH, although ALP activity remained elevated compared with controls. Conclusion. Vitamin D deficiency during gestation leads to profound disturbances in calcium–phosphorus homeostasis, whereas timely cholecalciferol supplementation promotes its restoration and may prevent pregnancy complications