Serum erythropoietin during normal pregnancy: relationship to hemoglobin and iron status markers and impact of iron supplementation in a longitudinal, placebo-controlled study on 118 women.
Serum erythropoietin (EPO) and its relationship to hemoglobin (Hb), iron status markers and iron supplementation during normal pregnancy was assessed in a longitudinal, placebo-controlled study on 118 women, 61 took daily tablets containing 66 mg ferrous iron from the second trimester until delivery and 57 took placebo. Blood samples were obtained at 4-week intervals until delivery as well as post-partum. In the placebo-treated women, median serum EPO rose from 22.5 U/l at inclusion to 35.0 U/l at delivery (P = 0.0001). In the iron-treated women, median serum EPO rose from 23.9 to 29.9 U/l (P = 0.0001). Serum EPO showed a steeper increase in the placebo-treated women than in the iron-treated women (P < 0.05). After delivery, serum EPO became normal in both groups (P = 0.0001). Median Hb was lower in placebo-treated (iron depleted) than in iron-treated (iron repleted) women (P < 0.05). In the placebo-treated women there was a negative correlation and in the iron-treated women a positive correlation between serum EPO and Hb. In the placebo-treated women, inverse correlations existed between serum EPO and serum transferrin saturation and serum ferritin, reflecting the consequences of iron deficiency, whereas the iron-treated women displayed no correlation. A physiological, nonhypoxia-induced increase in EPO production accounts for the basic expansion of the red cell mass during pregnancy. In placebo-treated women, iron deficient erythropoiesis constitutes an additional hypoxic stimulus, which induces a further increase in serum EPO.
Milman
N
N
Department of Medicine, Nastved Hospital, Denmark.
Graudal
N
N
Nielsen
O J
OJ
Agger
A O
AO
D000747:Anemia, Hypochromic / Q000517:prevention & control; D004311:Double-Blind Method; D004920:Erythropoiesis / Q000502:physiology*; D004921:Erythropoietin / Q000097:blood*; D005260:Female; D005293:Ferritins / Q000097:blood; D005296:Ferrous Compounds / Q000008:administration & dosage; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D000860:Hypoxia / Q000097:blood; D007501:Iron / Q000008:administration & dosage / Q000097:blood*; D000090463:Iron Deficiencies; D008137:Longitudinal Studies; D010928:Placental Lactogen / Q000097:blood; D049590:Postpartum Period / Q000097:blood; D011247:Pregnancy / Q000097:blood*; D011250:Pregnancy Complications, Hematologic / Q000517:prevention & control; D014168:Transferrin / Q000032:analysis
D005296:Ferrous Compounds; D006454:Hemoglobins; D014168:Transferrin; D004921:Erythropoietin; D005293:Ferritins; D010928:Placental Lactogen; D007501:Iron; C031621:ferrous fumarate