Vitamin D insufficiency as a risk factor for reproductive losses in miscarriage

Abstract

Objective To study the relationship between vitamin D deficiency, VDR gene polymorphism rs10735810 (A > G), and a missed abortion in the first trimester of gestation; to determine the predictors of its risk. Research methods 178 women aged between 18 and 41 were surveyed. The main group consisted of patients with miscarriage (n = 101), verified at the hospital stage (O02.0; O02.1), which were stratified by I group (n = 58, patients with the first miscarriage) and II groups (n = 43, patients with repeated miscarriage). The control group (n = 77) consisted of women with a successful pregnancy (Z34.0), which subsequently ended in delivery at term with a live fetus. Patients were surveyed and data was extracted from primary medical records. The level of 25(OH)D in the blood serum was investigated by mass spectrometry (n = 99). Genotyping for the vitamin D receptor gene polymorphism rs10735810 (VDR A > G) was performed for 177 patients. Statistical data analysis was performed via Statistica 10 and SAS JMP 11 application packages, using single-factor prediction for quantitative and binary factors, ROC analysis, and CHAID decision tree construction. Results of the study WE found that patients with miscarriage in the first trimester of gestation (n = 60) more frequently than those in the control group (n = 39) had vitamin D insufficiency (93.3% versus 76.9%, p = .0183) including its deficiency, occurring at 25(OH)D of blood <20 ng/ml (71.7% versus 51.3%, p = .0392). This pattern was found in patients with the first miscarriage, where significant differences in the frequency of vitamin D deficiency were also detected in comparison with the control group (80.0% versus 51.3%, p = .0026). No direct correlation was found between the frequency of miscarriages in the first trimester and the variant of the polymorphism of the vitamin D receptor gene (VDR A > G [rs10735810]); the GG genotype in patients with repeated miscarriages was even less frequent compared to the control group (14.0% versus 23.7%, p = .3344). However, the decision tree has identified four risk classes and has determined that the highest risk of missed abortion in the cohort studied is formed by three predicates: smoking, serum level 25(OH)D < 6.5 ng/ml and VDR AA and GG genotypes. Conclusion The data obtained show that vitamin D insufficiency plays a pathogenetically significant role in early reproductive losses associated with miscarriages, both first and recurrent.