Micronutrient status of women with impaired reproductive function in the Northwestern region of Russia

Background: In the modern world, the global population experiences metabolic syndrome pandemic as a result of micronutrient deficiencies. Intake levels of vitamin D, folates and polyunsaturated fatty acids vary in different populations. This issue is understudied among women with reproductive losses and infertility. Objective: To assess the micronutrient status (25-hydroxyvitamin D [25(OH)D], folic acid, omega-3 PUFAs) in the cohort of women in the Northwestern region of Russia, who have various reproductive impairments in history and evaluate relationship between impairments and the parameters of immunological profile. Materials and methods: The study included 299 women who had infertility in history. Their anamnestic data were obtained from the database of D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology (St. Petersburg) from 2017 to 2022. The patients were divided into 2 groups depending on their reproductive anamnesis. Group I (n=131) consisted of women with primary infertility. Group II (n=168) was comprised of women with secondary infertility, who had both emergency childbirth and one or more cases of reproductive loss (spontaneous abortion or missed miscarriage) in history. Further, at the stage of pregnancy planning (3 months before getting pregnant), different parameters of the micronutrient status in blood plasma and serum and immunological profile in the peripheral blood were evaluated in these groups of women. The micronutrient status was evaluated using the following techniques: chemiluminescent microparticle immunoassay was used to assess 25(OH)D circulating form of vitamin D levels in serum samples; chemiluminescent microparticle immunoassay (CMIA) was used to evaluate plasma homocysteine levels (the Laboratory of D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology); and gas chromatography-mass spectrometry was used to perform the Omega-3 Index test (the laboratory “Hemotest”). The assessment of immunological profile was performed by measuring the functional activity and the level of natural killer (NK) cells (the percentage (%) of NK cells (CD3-CD(16+56)+, the percentage (%) of NKT (CD3+CD(16+56)+, spontaneous NK cell activation (CD107a), activation of NK cells (CD107a) by flow cytometry. Antiphospholipid antibodies - lupus anticoagulant, antibodies against cardiolipin, β2 -glycoprotein, phosphatidylserine, phosphatidylic acid, phosphatidylinositol, annexin, prothrombin and the level of a human chorionic gonadotropin IgG (hCG IgG) antibodies were measured by ELISA (in the Department of Immunology and Intercellular Interactions, D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology). The following target values were determined for the patients of reproductive age: vitamin D≥30 ng/ml; homocysteine concentration <7 μmol/L; Omega-3 Index ≥ 8%. Results: In the group of women with primary infertility vitamin D level (n=55) was 31.90 (20.65; 40.75) ng/ml, whereas in the group with secondary infertility (n=74) it was 24.70 (18,00; 34,00) ng/ml. In both groups, median values of homocysteine were above target values and reached 7.7(6.0; 9.0) μmol/L (n=79) and 7.3(5.9; 3.6) μmol/L (n=100) in group I and group II, respectively. Omega-3 Index was 6,5 (5.1; 7.6)% in the group of women with primary infertility (n=14), and 5,2 (4,4; 5,9)% in the group of women with secondary infertility (n=42). However, there was no statistical difference between the groups (p<0.062). There was no statistically significant difference in the levels of vitamin D and homocysteine between the groups. Due to this, the subsequent analysis of these parameters was performed entirely regardless of the type of infertility in the general cohort of patients. Thus, in the general cohort of patients with infertility, vitamin D deficiency (<20 ng/ml) was in 38/129 (29,46%) women, insufficiency (20-30 ng/ml) was in 35/129 (27.13%), normal level was in 56/129 (43.41%) women. The target level of homocysteine (<7 μmol/L) was in 79/179 (44.13%) women, and non-target values (>7 μmol/L) were in 100/179 (55.87%) women. Omega-3 Index was critically low (<4%) in 5/56 (8.93%) women, insufficient (4-8%) in 46/56 (82.14%), and optimal (>8 %) in 5/56 (8.93%) women. Correlation analysis showed direct relationship between the mean values of vitamin D and Omega-3 Index (rs=0.5; p<0,01) and the level of homocysteine and human chorionic gonadotropin (hCG) antibodies (rs=0.5 p<0.01), as well as inverse relationships between vitamin D and immunological parameters: β2-glycoprotein antibodies (rs=-0.34; p=0,04), percentage (%) of NK (rs=-0.4; p=0.03); and Omega-3 Index and cardiolipin antibodies (rs=-0.47 p=0.03). There was no significant correlation between the other values. It has been shown, that the value of Omega-3 Index changes depending on the level of vitamin D (H=12.5; p=0.002). So, in women with vitamin D deficiency, the median level of Omega-3 Index was the lowest and reached 4.2 (3.8; 4.6) %, and was statistically significantly lower than in women with vitamin D insufficiency and reached 5.5 (4.6; 7.1)% (p=0.012), and it was lower than in patients with normal level of vitamin D, and this value was the highest and reached 5.85 (5.2; 6.9)% (p=0.002). In women with serum vitamin D level <20 ng/mL, there was a risk of identifying critically low level of Omega-3 level (OR=14.4 (1.23-168.51), p<0.05). Conclusion: According to the data in our study, the cohort of women with reproductive failures and infertility had a high prevalence of vitamin D deficiency, high level of homocysteine and low Omega-3 Index. Correlations between the micronutrient status and immunological profile were identified, which may be a factor that contribute to reproductive dysfunction

homocysteine, Omega-3 Index, vitamin D, pregravidary preparation, infertility, recurrent pregnancy loss