Vitamin B12 is correlated with insulin resistance and metabolism disorder markers in women with recurrent pregnancy loss.

OBJECTIVES

Recurrent pregnancy loss (RPL) seriously affects women's reproductive and mental health, and the incidence has increased in recent years. Insulin resistance (IR) acts as a significant contributing factor to RPL. Studies suggest that vitamin B12, folate intake, and homocysteine are correlated with IR, but the exact nature remains controversial and requires further investigation. In this study, we aimed to assess the levels and correlations between vitamin B12-folate-homocysteine and insulin resistance in RPL patients.

STUDY

DESIGN

73 control subjects and 256 RPL patients (144 RPL patients without IR and 112 RPL patients with IR) were included in this observational retrospective cross-sectional study. The differences in vitamin B12, folate, and homocysteine levels between RPL patients with and without IR were analyzed using a Student's t-test. Pearson correlations were utilized to examine the correlation between vitamin B12-folate-homocysteine and glucose and lipid metabolism parameters. Multivariable linear regressions were used to assess the independent correlation of each factor with HOMA-IR.

RESULTS

Compared to the control subjects, RPL patients exhibited lower vitamin B12 (p < 0.001) and folate (p < 0.001), and higher homocysteine (p = 0.001). RPL patients with IR described decreases in vitamin B12 (p = 0.003) and folate (p = 0.028), and increases in homocysteine (p = 0.033) as RPL patients without IR. Vitamin B12 in RPL patients was significantly negatively correlated with homocysteine (r = -0.348, p < 0.001), HOMA-IR (r = -0.214, p < 0.001), BMI (r = -0.160, p = 0.017), TG (r = -0.148, p = 0.039) and CHO (r = -0.149, p = 0.038) and positively correlated with folate (r = 0.217, p < 0.001). In multivariable linear regressions, after adjusting for age, strong correlations were observed between vitamin B12 (β = -0.197, p = 0.010), BMI (β = 0.466, p < 0.001), and HOMA-IR in RPL patients.

CONCLUSION

Vitamin B12 is significantly correlated with IR in RPL patients. Circulating vitamin B12-folate-homocysteine metabolism could be a window of the pathological process of IR, obesity, and lipid metabolism disorders in RPL patients.