Prospective and Longitudinal Study of Iron Metabolism Indicators During Normal Pregnancy in Chinese Women

The aim of this study was to investigate the changes in selected iron metabolism parameters during different periods of normal pregnancy and to establish reference values for these parameters related to gestational age.

Primipara women with a singleton pregnancy at 10 - 14 weeks of gestation were selected from women who attended the prenatal clinic at West China Second University Hospital from September 2016 to August 2017. The participants comprised 207 healthy Chinese women with a normal pregnancy. Blood samples were obtained at 10 - 14, 20 - 24, and 30 - 34 weeks of gestation, and at 6 - 12 weeks postpartum. The following parameters were measured: Ret-He, hs-CRP, serum ferritin (SF), sTfR, serum iron (SI), Tf, TIBC, and transferrin saturation (TS).

The respective reference values for healthy pregnant women in the three trimesters of pregnancy and at 6 - 12 weeks postpartum were: Ret-He: 29.8 - 39.6, 29.2 - 40.8, 26.2 - 41.0, and 26.8 - 38.5 pg; SF: 14 - 133, 7 - 130, 5 - 110, and 10 - 140 ng/mL; sTfR: 0.4 - 2.0, 1.2 - 3.0, 2.3 - 5.2, and 0.3 - 2.4 mg/L; SI: 6.0 - 31.0, 3.7 - 30.3, 4.7 - 49.4, and 4.5 - 26.8 μmol/L; Tf: 2.0 - 3.7, 2.2 - 4.4, 2.3 - 5.3, and 1.8 - 3.7 g/L; TIBC: 40 - 84, 52 - 100, 54 - 120, and 43 - 83 μmol/L; TS: 12 - 54%, 10 - 56%, 5 - 65%, and 10 - 52%.

Significant changes in iron parameters during pregnancy and postpartum were noted. It is important to learn these alterations and establish reference values to help obstetricians make clinical decisions.