Changes of iron metabolism during pregnancy and the establishment of reference intervals for pregnant Chinese women.

Abstract

Background Abnormalities of iron metabolism in pregnancy pose risks for maternal and fetal health. Robust reference intervals for iron metabolism indices have not been established in a pregnant Chinese population. The purpose of this study was to derive reference intervals for indices of iron metabolism during pregnancy in a Chinese population. Methods A total of 360 healthy pregnant women were recruited and divided into three groups of 120 by gestational age: first trimester (1–13 weeks), second trimester (14–27 weeks) and third trimester (≥28 weeks). An additional 120 healthy non-pregnant women were recruited as the non-pregnant control group. Serum ferritin was measured by electrochemiluminescence immunoassay. Serum iron and total iron-binding capacity were measured by a direct bathophenanthroline method. Transferrin saturation value was calculated with formula TS = SI/TIBC. The reference intervals were established using a non-parametric method. Results In first and second trimesters (combined), the reference intervals for serum ferritin, serum iron, total iron-binding capacity and transferrin saturation are 14.7–184.3 mg/L, 14.50–33.45 µmol/L, 36.53–68.81 µmol/L and 19.04–64.76%, respectively. In the third trimester, the reference intervals for serum ferritin, serum iron, total iron-binding capacity and transferrin saturation are 7.2–122.2 mg/L, 5.83–21.52 µmol/L, 49.40–122.76 µmol/L and 8.22–52.75%, respectively. Conclusion The reference intervals for iron metabolism indices for healthy pregnant Chinese women were established in accordance with CLSI C28-A3 guidelines. This will be a valuable tool for clinical practice and research.