Pregnancy support- Vitamin Deficiencies

Iron - updated: 03 November 2008

Body iron and individual iron prophylaxis in pregnancy--should the iron dose be adjusted according to serum ferritin?

Ann Hematol. 2006 Sep;85(9):567-73. Epub 2006 May 30

Milman N, Byg KE, Bergholt T, Eriksen L, Hvas AM.

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 microg/l in pregnancy and <15 microg/l postpartum; IDA as serum ferritin <12 microg/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 70 microg/l. At 32 weeks, women with ferritin 30 microg/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 microg/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 microg/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 70 microg/l have no need for iron supplement.

Publication Types:

• randomised, double-blind study

Iron prophylaxis during pregnancy -- how much iron is needed? A randomized dose- response study of 20-80 mg ferrous iron daily in pregnant women

Acta Obstet Gynecol Scand. 2005 Mar;84(3):238-47

Milman N, Bergholt T, Eriksen L, Byg KE, Graudal N, Pedersen P, Hertz J.

OBJECTIVE: To determine the lowest dose of iron preventative of iron deficiency and iron deficiency anemia in pregnancy. METHODS: A randomized, double-blind intention-to-treat study comprising 427 healthy pregnant women allocated into four groups taking ferrous iron (as fumarate) in doses of 20 mg (n = 105), 40 mg (n = 108), 60 mg (n = 106), and 80 mg (n = 108) from 18 weeks of gestation. Iron status markers [hemoglobin (Hb), serum ferritin, and serum soluble transferrin receptor (sTfR)] were measured at 18 weeks (inclusion), 32 weeks, and 39 weeks of gestation and 8 weeks postpartum. Side effects of iron supplements were recorded. Iron deficiency was defined as serum ferritin <13 microg/l and iron deficiency anemia as serum ferritin <13 microg/l and Hb <5th percentile in iron replete pregnant women. RESULTS: There were no significant differences between variables in the four groups at inclusion. At 32 and 39 weeks of gestation, group 20 mg had significantly lower median serum ferritin (13 and 16 microg/l) than group 40 mg (17 and 21 microg/l), group 60 mg (18 and 23 microg/l), and group 80 mg (21 and 24 microg/l) (p < 0.0001). At 32 and 39 weeks of gestation, group 20 mg had a significantly higher prevalence of iron deficiency (50 and 29%) than group 40 mg (26 and 11%), group 60 mg (17 and 10%), and group 80 mg (13 and 9%) (p < 0.001). The prevalence of iron deficiency anemia at 39 weeks of gestation was significantly higher in group 20 mg (10%) than in group 40 mg (4.5%), group 60 mg (0%), and group 80 mg (1.5%) (p = 0.02). At 32 weeks of gestation, mean Hb in group 20 mg was lower than in group 80 mg (p = 0.06). There were no significant differences in iron status (ferritin, sTfR, and Hb) between group 40, 60, and 80 mg. Postpartum, group 20 mg had significantly lower median serum ferritin than group 40, 60, and 80 mg (p < 0.01). The prevalence of postpartum iron deficiency anemia was low and similar in the four groups. The frequency of gastrointestinal symptoms was not significantly different in the four iron supplement groups and thus not related to the iron dose. CONCLUSION: In Danish women, a supplement of 40 mg ferrous iron/day from 18 weeks of gestation appears adequate to prevent iron deficiency in 90% of the women and iron deficiency anemia in at least 95% of the women during pregnancy and postpartum.

Publication Types:

• randomized, double-blind intention-to-treat study

Iron supplementation in pregnancy

J Perinat Med. 2003;31(5):420-6

Müngen E.

Iron deficiency is the most common nutritional disorder in the world. Pregnant women are at especially high risk for iron deficiency and iron deficiency anemia. A considerable proportion of pregnant women in both developing and industrialized countries become anemic during pregnancy. The prevalence of anemia in pregnant women has remained unacceptably high worldwide despite the fact that routine iron supplementation during pregnancy has been almost universally recommended to prevent maternal anemia, especially in developing countries over the past 30 years. The major problem with iron supplementation during pregnancy is compliance. Despite many studies, the relationship between maternal anemia and adverse pregnancy outcome is unclear. However, there is now sufficient evidence that iron supplements increase hemoglobin and serum ferritin levels during pregnancy and also improve the maternal iron status in the puerperium, even in women who enter pregnancy with adequate iron stores. Recent information also suggests an association between maternal iron status in pregnancy and the iron status of infants postpartum. The necessity of routine iron supplementation during pregnancy has been debated in industrialized countries and routine supplementation is not universally practiced in all these countries. In view of existing data, however, routine iron supplementation during pregnancy seems to be a safe strategy to prevent maternal anemia in developing countries, where traditional diets provide inadequate iron and where malaria and other infections causing increased losses are endemic.

Publication Types:

• Review

Iron supplementation during pregnancy: what are the risks and benefits of current practices?

Appl Physiol Nutr Metab. 2007 Apr;32(2):282-8

Rioux FM, LeBlanc CP.

Iron-deficiency anemia is still prevalent among pregnant women living in industrialized countries such as Canada. To prevent this deficiency, iron supplements (30 mg/d) are routinely prescribed to Canadian pregnant women. Recently, dietary reference intakes for iron have increased from 18 and 23 mg/d during the second and third trimesters, respectively, to 27 mg/d throughout the pregnancy for all age groups. Whether this new recommendation implies an increase of iron dosage in supplements has not been answered. Are there any benefits or risks for the mother and her infant associated with iron supplementation during pregnancy? If iron supplementation is recommended, what should be the ideal dosage? This article reviews current knowledge on the potential negative or positive impact of iron supplementation during pregnancy on the outcomes of both infants and mothers. Based on the literature reviewed, a low daily dose of iron (30 mg elemental iron) during pregnancy improves women's iron status and seems to protect their infants from iron-deficiency anemia. Several studies have also shown that a low daily dose of iron may improve birth weight even in non-anemic pregnant women. However, higher dosages are not recommended because of the potential negative effects on mineral absorption, oxidative pathways, and adverse gastrointestinal symptoms. To date, it is still not clear if health professionals should recommend routine or selective supplementation. However, neither routine nor selective iron supplementation during pregnancy is able to eliminate iron-deficiency anemia. Even though the dietary reference intake for iron during pregnancy has been recently increased, we do not recommend higher doses of iron in supplements designed for pregnant women.

Publication Types:

• Review

Effect of high-dose iron supplements on fractional zinc absorption and status in pregnant women

Am J Clin Nutr. 2007 Jan;85(1):131-6

Harvey LJ, Dainty JR, Hollands WJ, Bull VJ, Hoogewerff JA, Foxall RJ, McAnena L, Strain JJ, Fairweather-Tait SJ.

BACKGROUND: Women have an increased risk of iron deficiency during pregnancy because of the demands of the developing fetus. Iron supplements are commonly advocated as a prophylactic treatment and are generally taken with meals to reduce side effects, but iron can interfere with the absorption of zinc. OBJECTIVE: The aim was to determine the effect of consuming an iron supplement (100 mg Fe/d as ferrous gluconate) with meals from 16 wk gestation to term on zinc status and absorption. DESIGN: Stable-isotope techniques were used to measure zinc status (exchangeable zinc pool, EZP) and fractional zinc absorption (FZA) in early and late pregnancy from a meal consumed at a different time from that of iron supplement or placebo consumption in 6 women given iron supplements and 7 given a placebo. RESULTS: FZA increased during pregnancy, independent of iron supplementation. FZA was significantly higher (P < 0.001) at week 34 than at weeks 16 and 24, and urinary zinc excretion was higher at week 34 than at week 16 (P = 0.02). The size of the EZP remained unchanged throughout pregnancy and was unaffected by iron supplementation. The iron status of iron-supplemented women was higher than that of the placebo group. CONCLUSIONS: In iron-replete pregnant women who consumed a Western diet, no detectable adverse effects on zinc metabolism were observed after ingestion of 100 mg Fe/d. An increase in the efficiency of zinc absorption was observed during late pregnancy.

Publication Types:

• Placebo Controlled

The importance of iodine nutrition during pregnancy

Public Health Nutr. 2007 Dec;10(12A):1542-6

Glinoer D.

OBJECTIVE: To examine the importance of iodine nutrition during pregnancy.DESIGN: Review of existing literature of iodine in pregnancy. SETTING: Population surveys and metabolic studies. SUBJECTS: Pregnant women. RESULTS: The main changes in thyroid function associated with pregnancy are due to an increase in hormone requirements that begin in the first trimester of gestation. This increase can only be met by a proportional increase in hormone production, something that depends directly upon the availability of iodine. When dietary iodine is lacking, an adequate physiological adaptation is difficult to achieve and is progressively replaced by pathological alterations that occur in parallel with the degree and duration of iodine deprivation.CONCLUSIONS: Iodine prophylaxis should be given systematically to women during pregnancy. In most public health programmes dealing with the correction of iodine deficiency disorders, iodised salt has been used as the preferred means to deliver iodine to households. Iodised salt, however, is not the ideal means of delivering iodine in the specific instances of pregnancy, breast-feeding and complementary feeding because of the need to limit salt intake during these periods. In European countries, presently it is proposed that iodine is given to pregnant women and breast-feeding mothers by systematically administering multivitamin tablets containing iodine in order to reach the recommended dietary allowance of 250 microg iodine day-1.

Publication Types:

• Review

Iron deficiency and child development

Food Nutr Bull. 2007 Dec;28(4 Suppl):S560-71.

Lozoff B.

Iron deficiency is widespread in infants and young children, especially in developing countries. Animal models provide convincing evidence that, despite iron repletion, iron deficiency during the brain growth spurt alters metabolism and neurotransmission, myelination, and gene and protein profiles. In the human, there is compelling evidence that 6- to 24-month-old infants with iron-deficiency anemia are at risk for poorer cognitive, motor, social-emotional, and neurophysiologic development in the short- and long-term outcome. In contrast to inconsistent developmental effects of iron therapy for iron-deficient infants, recent large, randomized trials of iron supplementation in developing countries uniformly show benefits of iron, especially on motor development and social-emotional behavior. These results indicate that adverse effects can be prevented and/or reversed with iron earlier in development or before iron deficiency becomes severe or chronic. New findings also point to the need for more attention to the developmental effects of prenatal iron deficiency.

Publication Types:

• Review

Iron deficiency and brain development

Semin Pediatr Neurol. 2006 Sep;13(3):158-65

Lozoff B, Georgieff MK.

Iron deficiency (ID) is common in pregnant women and infants worldwide. Rodent models show that ID during gestation/lactation alters neurometabolism, neurotransmitters, myelination, and gene/protein profiles before and after iron repletion at weaning. Human infants with iron deficiency anemia test lower in cognitive, motor, social-emotional, and neurophysiologic development than comparison group infants. Iron therapy does not consistently improve developmental outcome, with long-term differences observed. Poorer outcome has also been shown in human and monkey infants with fetal/neonatal ID. Recent randomized trials of infant iron supplementation show benefits, indicating that adverse effects can be prevented and/or reversed with iron earlier in development or before ID becomes severe or chronic. This body of research emphasizes the importance of protecting the developing brain from ID.

Publication Types:

• Review

Publication Types:

• Review