Introduction:
To explore the changes and correlation of serum 25-hydroxyvitamin-D3, high-sensitivity C-reactive protein (hs-CRP), and homocysteine (Hcy) in patients with gestational diabetes mellitus (GDM).

Material and methods:
A total of 110 GDM patients from September 2019 to September 2020 constituted the GDM group, and 100 pregnant women with a normal 75 g oral glucose tolerance test (OGTT) throughout the same duration constituted the control group. General information of the patients was collected: maternal age, BMI, gravidity, parity, and the gestational week at the time of glucose tolerance screening. Serum levels of 25-(OH)2 -VitD3 , hs-CRP, and Hcy were compared between the two groups. Pearson correlation analysis was used to evaluate the correlation between 25-(OH)2 -VitD3 , hs-CRP, Hcy, and homeostasis model assessment of insulin resistance index (HOMA-IRI) in GDM patients.

Results:
Serum 25-(OH)2 -VitD3 levels in the GDM group and control group were 15.67 ±3.62 and 18.66 ±3.41 ng/ml, hs-CRP levels were 6.07 ±1.45 and 3.12 ±1.07 mg/l, and serum Hcy levels were 17.03 ±4.10 and 8.63 ±2.27 µmol/l. Serum 25-(OH)2 -VitD3 levels in the GDM group were substantially lower than those in the control group, while hs-CRP, Hcy, and HOMA-IRI in the GDM group were significantly higher than those in the control group (p < 0.05). Pearson correlation analysis demonstrated that serum 25-(OH)2 -VitD3 levels in the GDM group were negatively correlated with HOMA-IRI. In contrast, hs-CRP and Hcy levels were substantially positively correlated with HOMA-IRI (p < 0.01).

Conclusions:
Blood levels of 25-(OH)2 -VitD3 , hs-CRP, and Hcy levels can be a potential indicator of GDM.