Iron supplementation-induced modulation of hepcidin, erythroferrone, and oxidative balance in iron-deficient pregnant women

Iron deficiency anemia affects approximately 40% of pregnant women worldwide, associated with increased oxidative stress (OS) and adverse pregnancy outcomes. Recent advances identified hepcidin as the master regulator of iron homeostasis and erythroferrone (ERFE) as a key erythroid regulator, yet their responses to iron supplementation and relationships with OS markers during pregnancy remain poorly understood. To investigate whether oral iron supplementation reduces OS in pregnant women with IDA and characterize relationships between iron regulatory molecules (hepcidin, ERFE) and OS biomarkers. This single-arm observational study without placebo controls enrolled 40 pregnant women with IDA (mean age 29.23 ± 6.33 years) across all trimesters. Participants received 200 mg elemental iron daily for one month. Pre- and post-treatment measurements included hematologic parameters, iron metabolism markers (ferritin, hepcidin, ERFE), and OS biomarkers (total antioxidant status TAS, total oxidant status TOS). Iron supplementation was associated with significant improvements in TAS (0.96 ± 0.36 to 1.64 ± 0.37mmol Trolox Equiv./L; Cohen’s d = 1.87, p < 0.001), exceeding hematological improvements in hemoglobin (10.10 ± 0.72 to 11.61 ± 0.97 g/dL; d = 1.76, p < 0.001) and hematocrit (30.93 ± 1.79% to 35.24 ± 3.01%; d = 1.74, p < 0.001). The TOS/TAS ratio decreased significantly (14.53 ± 15.98 to 4.10 ± 3.14 U/mmol Trolox Equiv.; d = -0.91, p < 0.001). Hepcidin increased (2214.62 ± 1444.27 to 3492.65 ± 1640.51 pg/mL; d = 0.83, p < 0.001) while ERFE decreased (470.75 ± 170.75 to 345.25 ± 112.96 pg/mL; d = -0.87, p < 0.001), consistent with successful iron repletion. Notably, significant Trimester × Time interactions were observed for both hormones (hepcidin: ηp2 = .452; ERFE: ηp2 = .462, both p < 0.001), with hepcidin elevation progressively increasing across trimesters and ERFE suppression maximal during second trimester. TAS improvements showed minimal correlation with iron parameters (all |r|< 0.25), suggesting potentially independent mechanisms. Iron supplementation was associated with reduced OS in pregnant women with IDA through mechanisms potentially independent of iron parameter changes. The coordinated hormonal responses are consistent with appropriate iron repletion while suggesting additional therapeutic benefits beyond anemia correction.