Diagnostic performance and discriminative value of the serum ferritin level for predicting preterm labor

BACKGROUND The measuring serum ferritin level as a sensitive inflammatory biomarker might effectively predict preterm delivery, but the power and the best cut-off point of this biomarker for predicting preterm labor in Iranian population has not been substantially identified. Our purpose was to determine what concentrations of serum ferritin could identify patients at risk for preterm delivery in Iranian population for the first time. MATERIALS AND METHODS This case control study involved 222 singleton pregnancies that were referred to referral university hospitals clinics in Isfahan. Women with spontaneous preterm delivery before 24-26 weeks (preterm delivery group, n = 69) and those who delivered at term (term delivery group, n = 153) were compared with respect to serum ferritin concentration. Venous blood samples were analyzed for the serum ferritin level using the ferritin quantitative test system-sensitive for the normal ferritin range. RESULTS Women who delivered before 37 weeks had a higher mean serum ferritin concentration than those who delivered after 37 weeks of gestation (26.7 ± 5.5 ng/mL versus 19.8 ± 3.6 ng/mL, P<0.001). A serum ferritin level of 22.5 ng/mL yielded the best combination with sensitivity of 78.3%, specificity of 83.0%, positive predictive value of 67.5%, and negative predictive value of 89.4% for prediction of preterm delivery. CONCLUSION The serum ferritin level provides an appropriate discrimination in predicting preterm delivery with an optimal cut-off value of 22.5 ng/mL in Iranian population.