Iron supplementation in pregnant Danish women revisited: Effects on prepartum and postpartum iron deficiency, anemia, serum erythropoietin; including iron status, erythropoietin and anthropometrics in newborns. A randomized, placebo-controlled study.

Objective: To assess effects of iron supplementation, 66 mg elemental iron daily as ferrous fumarate, on iron status markers during normal pregnancies.

Methods: Randomized, double-blind, placebo-controlled study of 119 women (62 iron-, 57 placebo -treated) and their newborns. Hemoglobin (Hb), serum (S)-ferritin, S-transferrin saturation percentage (TSAT) and S-erythropoietin (S-EPO) were measured at 14-18, 24-27 weeks of gestation, prepartum, 1 and 8 weeks postpartum.

Result: From 24-27 weeks gestation to 8 weeks postpartum, the iron group had higher Hb, S-ferritin and TSAT than the placebo group; prepartum, 11% had iron deficiency (ID) and 0% iron deficiency anemia (IDA) in the iron group, vs 60% and 18% in the placebo group; 8 weeks postpartum 1.6% in the iron group had ID and 1.6% IDA vs 14% and 7% in the placebo group. S-EPO levels in the iron group were lower than in the placebo group (p < 0.001). Mothers prepartum S-EPO values were correlated to newborns cord S-EPO values (p < 0.001). Newborns to iron treated mothers had higher cord S-ferritin levels than those to placebo treated mothers (p = 0.02). Newborn girls had higher cord S-ferritin levels than boys (p < 0.01). There was no impact of iron supplementation on the length of gestation, placental weight, or newborns birth weight. Birth weight was correlated only with mothers' body weight, length of gestation and placental weight.

Conclusion: Iron supplementation had a "positive" impact on iron status and Hb both during pregnancy and postpartum, with a low frequency of ID/IDA and also a "positive" influence on newborns iron status.