Maternal plasma concentrations of macrophage migration inhibitory factor at first trimester as a predictive biomarker of preterm delivery in Chinese women.

BACKGROUND: Infection and/or inflammation have been proposed play role in the preterm delivery (PTD) pathogenesis. Macrophage migration inhibitory factor(MIF), a mediator of innate immunity and inflammation, is induced in various infections, including those that occur during pregnancy. We assessed the relation between maternal early pregnancy plasma concentrations of MIF and PTD.

METHODS: Women were recruited before 14 weeks gestation and were followed up until delivery. Maternal plasma concentrations of MIF, C-reactive protein (CRP) and interleukin 6 (IL-6) at first visit were measured by competitive immunoassay. The diagnosis of PTD was made using American College of Obstetricians and Gynaecologists (ACOG) guidelines. Logistic regression procedures were used to calculate adjusted odds ratio (OR) and 95% confidence intervals (95%CI).

RESULTS: In the study period, 596 participants were included. The median plasma concentration of MIF was significantly higher in women in whom PTD later developed compared with those delivering at term (P < 0.001). For each 1 ng/ml increase of plasma concentration of MIF, the unadjusted and adjusted risk of PTD would be increased by 12% (with the OR of 1.12 [95% CI 1.07-1.17], P < 0.001) and 7% (1.07 [1.02-1.15], P = 0.002), respectively. Stratified analyses indicated that increased MIF was associated with an increased risk of spontaneous delivery (OR = 1.16, 95%CI: 1.07-1.24; P < 0.001), indicated delivery (OR = 1.05, 95%CI: 1.01-1.14; P = 0.02), and before 34 weeks' gestation delivery (OR = 1.09, 95%CI: 1.03-1.18). With an AUC of 0.71, MIF showed a significantly greater discriminatory ability as compared with BMI (0.58; 95% CI: 0.52-0.65; P < 0.001), CRP (0.61; 95% CI: 0.54-0.68; P < 0.001) and IL-6(0.63; 95% CI: 0.55-0.69; P = 0.001).

CONCLUSIONS: Increased maternal plasma concentrations of MIF at first trimester were associated with increased risk of PTD and might be useful in identifying newborn at risk for PTD for early prevention strategies.