Serum Ferritin Concentration in the Early Third Trimester of Pregnancy and Risk of Preterm Birth and Low Birth Weight Based on Gestational Age

Abstract

Objective: Although serum ferritin is considered the best measure of total body iron, with low levels indicating iron deficiency, recent studies have shown that high levels are associated with gestational diabetes, premature birth, and low birth weight. This study aimed to analyze the association between serum ferritin levels in the third trimester of pregnancy and low birth weight and preterm birth.Methods: This study included pregnant women who delivered a single fetus at Kangwon National University Hospital between January 2009 and December 2013 and in whom serum ferritin levels were measured between 28 and 34 weeks of gestation. The association between serum ferritin levels measured in the early third trimester of pregnancy and preterm birth and low birth weight infants was analyzed.Results: A total of 1,079 women fulfilled the study criteria and had their serum ferritin level measured during the third trimester (28–33.9 weeks of gestation) and later delivered at Kangwon National University Hospital. Comparison of the group with serum ferritin levels above the 75th percentile and those below the 25th percentile at the beginning of the third trimester revealed that the incidence of preterm births (<34 weeks of gestation, <37 weeks of gestation) and low birth weight were significantly higher in the group with serum ferritin levels above the 75th percentile than those below the 25th percentile (p<0.05). When variable factors were controlled through multiple regression analysis, the group whose serum ferritin levels were above the 75th percentile at 30–31.9 weeks of gestation had the highest risk of preterm birth before 34 weeks of gestation (adjusted odds ratio [OR], 7.85; 95% confidence interval [CI], 1.32–29.9) and low birth weight (adjusted OR, 6.49; 95% CI, 2.10–20.0).Conclusion: In this study, when serum ferritin was high in the third trimester of pregnancy, it was significantly increased with preterm birth (<34 and 37 weeks) and low birth weight. In particular, when serum ferritin levels were high at 30–31.9 weeks of gestation, the risk of premature birth before 34 weeks and low birth weight was statistically highest.