Maternal serum folate species in early pregnancy and lower genital tract inflammatory milieu

OBJECTIVE: We previously reported that elevated antiinflammatory cervical cytokines in early pregnancy were associated with spontaneous preterm birth. Our objective was to explore the relation between serum folate vitamers and the lower genital tract inflammatory milieu. STUDY DESIGN: Pregnant women (n = 417) at <16 weeks' gestation had serum samples that were analyzed for folate species 5-methyltetrahydrofolate, 5-formyltetrahydrofolate, and cervical fluid that was assayed for cytokine concentrations. Patterns in proinflammatory cytokines (interleukin [IL]-1 beta, -6, -8, and -10; monocyte chemotactic protein-1) and antiinflammatory cytokines (IL-4, IL-10, IL-13) were identified with factor analysis. RESULTS: After confounder adjustment, maternal serum 5-methyltetrahydrofolate concentrations had a strong negative association with elevated antiinflammatory scores; serum 5-formyltetrahydrofolate concentrations were associated positively with elevated antiinflammatory scores (both P < .05). Maternal folate was not associated with proinflammatory scores. CONCLUSION: Maternal serum folate vitamers are associated with cervical cytokine concentrations, which suggests a possible mechanistic link between folate and preterm birth risk.