RESUMO
BACKGROUND The aim of this study was to evaluate the association of maternal serum 25-hydroxyvitamin D, paraoxonase 1, and neutrophil-to-lymphocyte ratio in women having early spontaneous preterm birth without clinical chorioamnionitis. MATERIAL AND METHODS This study was prospectively administered in women referred to our obstetrics service with preterm labor that resulted in preterm birth (n=35) and term labor that ended in term birth (n=44). The maternal serum levels of 25-hydroxyvitamin D and paraoxonase 1 were measured and neutrophil-to-lymphocyte ratio was calculated. RESULTS The 25-hydroxyvitamin D and paraoxonase 1 levels of the preterm group were significantly lower than those of the term group (p<0.05). The neutrophil-to-lymphocyte ratio value of the preterm group was significantly higher than that of the term group (p<0.05). There was a significant but small positive correlation between the serum levels of 25-hydroxyvitamin D and paraoxonase 1 in the preterm group (r=0.35; p=0.021). CONCLUSIONS Decreased maternal serum 25-hydroxyvitamin D and paraoxonase 1 levels and increased neutrophil-to-lymphocyte ratio may have a role in the etiology of spontaneous preterm birth.