Body iron and individual iron prophylaxis in pregnancy—should the iron dose be adjusted according to serum ferritin?
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This study aims to evaluate iron prophylaxis in pregnant women from the individual aspect, i.e. according to serum ferritin levels at the beginning of pregnancy, and to assess which dose of iron would be adequate to prevent iron deficiency (ID) and iron deficiency anaemia (IDA) during pregnancy and postpartum. A randomised, double-blind study comprising 301 healthy Danish pregnant women allocated into four groups taking ferrous iron (as fumarate) in doses of 20 mg (n=74), 40 mg (n=76), 60 mg (n=77) and 80 mg (n=75) from 18 weeks gestation (inclusion) to 8 weeks postpartum. Iron status markers [serum ferritin, serum soluble transferrin receptor (sTfR), haemoglobin] were recorded at 18, 32 and 39 weeks gestation and 8 weeks postpartum. Body iron was calculated using the serum sTfR/serum ferritin ratio. ID was defined by serum ferritin <12 μg/l in pregnancy and <15 μg/l postpartum; IDA as serum ferritin <12 μg/l and haemoglobin <5th percentile in iron-replete pregnant women. Women in the iron supplement groups were stratified according to serum ferritin levels at inclusion; 50.7% had ferritin ≤30 μg/l, 37.7% ferritin 30–70 μg/l and 11.6% ferritin >70 μg/l. At 32 weeks, women with ferritin ≤30 μg/l had an ID frequency of: 20-mg group 54.1%, 40 mg 29.7%, 60 mg 24.4%, 80 mg 20.6% (p<0.001); women with ferritin >30 μg/l had an ID frequency of: 20-mg group 20.0%, 40 mg 13.9%, 60 mg 5.7%, 80 mg 5.1% (p<0.001). Women with ferritin >70 μg/l had no ID. Postpartum, ID was found in 4.7% in 20-mg group, 2.9% in group 40 mg and 0% in group 60 and 80 mg. IDA: At 32 weeks, women with ferritin ≤30 μg/l had an IDA frequency of: 20-mg group 2.7%, 40 mg 2.7%, 60 and 80 mg 0%; none of the women with ferritin >30 μg/l displayed IDA. Body iron at 18 weeks was 10.4 mg/kg, similar in the four iron groups. Later in pregnancy body iron declined significantly, being lower the 20 mg group, and similar in the 40, 60 and 80-mg groups. Postpartum body iron rose to inclusion levels being 9.3 mg/kg in the 20-mg group and 10.5 mg/kg in the 40-, 60- and 80-mg groups. This study gives an estimate of iron dosage in individual iron prophylaxis adjusted to serum ferritin levels in early pregnancy. In the prevention of ID, we suggest 80–100 mg ferrous iron/day to women having ferritin ≤30 μg/l and 40 mg ferrous iron/day to women having ferritin 31–70 μg/l. In the prevention of IDA, we suggest 40 mg ferrous iron/day to women having ferritin ≤70 μg/l. Women with ferritin >70 μg/l have no need for iron supplement.
KeywordsAnemia Iron deficiency Delivery Ferritin Hemoglobins Iron Pregnancy Puerperium Supplement Food
The study was supported by grants from Apotekerfonden and Den Lægevidenskabelige Forskningsfond ved Region 3. The authors appreciate the great help of the midwives at the Department of Obstetrics during the study and the enthusiasm of Chief Physician Robert Jordal† and the laboratory technicians at the Department of Clinical Biochemistry, Gentofte Hospital.
- 1.Bothwell TH (200) Iron requirements in pregnancy and strategies to meet them. Am J Clin Nutr 72(suppl 1):257S–264SGoogle Scholar
- 5.Nordic Council of Ministers (2004) Nordic nutrition recommendations 2004, 4th edn. Nord, Copenhagen, pp 364–366Google Scholar
- 10.Institute of Medicine, Food and Nutrition Board (1993) Iron deficiency anemia: recommended guidelines for the prevention, detection, and management among US children and women of childbearing age. National Academy, Washington, District of ColumbiaGoogle Scholar
- 14.Milman N, Juul-Jørgensen B, Bentzon MW (1997) Calibration of the Abbott AxSYM Ferritin kit using the WHO Human Liver Ferritin International Standard 80/602. Clin Chem 35:631–632Google Scholar
- 16.Worwood M (1994) Laboratory determination of iron status. In Brock, JH, Halliday JW, Pippard MJ, Powell LW (eds) Iron metabolism in health and disease. WB Saunders, London, pp 449–476Google Scholar
- 20.Skikne B, Baynes RD (1994) Iron absorption. In Brock JH, Halliday JW, Pippard MJ, Powell LW (eds) Iron metabolism in health and disease. Saunders, London, pp 151–187Google Scholar
- 24.Galan P, Wainer R, De Benaze C, Hercberg S (1990) Prevention de l’anemie ferriprive au cours de la grossesse: effet de la supplementation precoce en fer. In: Hercberg S, Galan P, Dupin H (eds) Recent knowledge on iron and folate deficiencies in the World. INSERM, Paris, 615–621Google Scholar
- 28.Thompson WG (1988) Comparison of tests for diagnosis of iron depletion in pregnancy. Am J Obstet Gynecol 5:1132–1134Google Scholar
- 30.Carriage MT, Skikne S, Finley B, Cutler B, Cook JD (1991) Serum transferrin receptor for the detection of iron deficiency. Am J Clin Nutr 54:107–181Google Scholar
- 33.Danish National Board of Health (1992) Recommendations about iron supplementation during pregnancy. Ugeskr Laeger 154:3445Google Scholar
- 34.Milman N (2006) Iron and pregnancy—a delicate balance. Ann Hematol May 12 (Epub ahead of print)Google Scholar
- 35.Nokes C, van den Bosch C, Bundy D (1998) The effects of iron deficiency and anemia on mental and motor performance, educational achievement, and behavior in children. A report of the INACG. International Life Sciences Institute, Washington, DCGoogle Scholar