Table 3 Effects of iron supplementation on hematologic parameters in low birth weight infants
From: Benefits of Iron supplementation for low birth weight infants: A systematic review
Study | Effect | No Effect | % of ID and/or IDA | Conclusion | Comments |
|---|---|---|---|---|---|
Hammond et al. 1960[22] | Hb, HCT significantly higher in T group by 3 mo; erythrocyte count significantly higher in T group by 5 mo | Blood volume, circulating Hb mass | 27.3 vs 7.7 % IDA (C vs T) | Early iron suppl. accelerates recovery from early IDA | 27 % loss to follow up; other vitamins were administrated; BW and hematologic measurements slightly higher in C vs T group |
Brozovic et al 1974[23] | At 3 mo of age, most infants had low serum iron concentrations, which remained low (6–9 mo) | NA | > 50 % IDA | Iron suppl. was insufficient to prevent IDA in most infants | No control group; all infants received vitamin K; some infants received other vitamins |
Lundstrom et al. 1977[2] | SF, Hb, MCV, TRNSAT significantly higher in T group by 3 mo | Reticulocyte count | 67 vs 0 % ID (C vs T) | LBW infants who do not receive iron suppl. may develop ID by 3 mo of age; 2 mg/kg/d iron is adequate for the prevention of IDA | 23 % loss to follow up; after 3 mo of age, an increasing number of C group infants were excluded; SF was higher than normal in C group; iron suppl. given in 2 different forms |
Iwai et al. 1986[24] | Hb, SF, MCV significantly higher in the formula group by 4 mo | RBC, SI, TIBC | 86 vs 33 % ID (human milk vs formula) | Breast-fed infants have a high risk of ID | Infants in formula group had slightly higher BW than those in human milk group; iron status of LBW infants was not evaluated |
Hall et al. 1993[25] | Hospitalization: plasma ferritin lowest in low iron group Discharge: plasma ferritin significantly lower in both formula groups 8 wks after discharge; MCV, MCH significantly lower in low iron group | Hb, HCT, reticulocyte, TRN, TRNSAT | 27, 69, 76 % IDA (high, low, human milk) | Preterm infants receive more benefit from receiving preterm infant formula containing 1.3 mg/kg/d iron vs 0.3 mg/kg/d | 44 and 25 % of infants in high and low dose groups dropped out because of prematurity related diseases; 13 % of infants in the human milk group completed the study |
Griffin et al. 1999[26] | NA | Hb | 18 vs 27 % ID (A vs B) | 0.81-1.17 mg/kg/d iron seems to meet the iron nutritional needs of preterm infants | In group C, BW was slightly lower, fewer transfusions were received, and Hb was significantly lower vs A and B; no ferritin data for Group C |
Franz et al. 2000[27] | NA | All markers of iron nutrition | 14.7 vs 40.0 % ID (T vs C) | Fewer infants in group T received blood transfusion vs group C; early iron suppl. is feasible and safe in LBW infants | 34 % loss to follow up; group C tended to have > chronic lung disease and ROP |
Friel et al. 2001[28] | NA | No difference in any hematologic parameters | 6.9 vs 13.8 % ID (normal vs high) | In terms of cognitive outcome, LBW infants did not benefit from high dose iron | No control group |
Aggarwal et al. 2005[29] | Adjusted Hb higher in T group | SF | NA | Iron suppl. marginally increases Hb in LBW infants | 42 % loss to follow up |
Miller et al. 2006[30] | NA | SI, SF, TIBC, sTfR | NA | Corrected reticulocyte count higher in the T group suggesting improved erythropoiesis | Iron suppl. was adjusted by individual iron status; CGA, weight, age at enrollment > in T group |
Arnon et al. 2007[31] | Hb, reticulocytes, iron, ferritin significantly higher in the 2 wk group at 8 wks | Reticulocytes, iron, ferritin at 4 wks of age | NA | Iron suppl. to preterm infants as early as 2 weeks of age was more beneficial for iron status, than at 4 weeks of age | All infants given 25 mg/d oral vitamin E; 35 % loss to follow up |
Braekke et al. 2007[33] | Iron, TRANSAT significantly increased | Ferritin | NA | Oral iron did not change markers of oxidative stress in LBW infants | No control group; all infants received other vitamins, including vitamin E; 15 % loss to follow up; short length of iron administration |
Sankar et al. 2009[34] | NA | SF, HCT, Hb | NA | Iron suppl. at 2 weeks of age did not improve hematological parameters at 2 mo of age in preterm very LBW infants | Iron suppl. group received folic acid and vitamin B12; uncommon iron formulation used |
Berglund et al. 2010[35] | All indicators of iron status differed significantly between groups in a dose-dependent manner | NA | 2.7, 0, 9.9 % IDA (T1, T2, C) 9.5, 3.8, 35.8 % ID (T1, T2, C) | Marginally LBW infants had higher risk of ID and IDA, especially those exclusively breastfed; 2 mg/kg/d oral iron significantly improved iron status and reduced IDA risk | NA |