Han 2011.

Methods	Quasi‐randomised control trial with 3 arms and individual allocation to groups by order of enrolment.
Participants	153 anaemic pregnant women 12 to 24 weeks' gestation, age range 20‐30 years, with 80 ≤ Hb <110 g/L, no dietary supplements use during the previous 2 months and no abnormal pregnancy response recruited from the communities of Shen county, Shandong province, China.
Interventions	Participants were allocated to 1 of the 3 groups in the order of enrolment: group 1 (n = 51) was the placebo control; group 2 (n = 51) received supplement daily containing 60 mg elemental iron (as ferrous sulphate); group 3 (n = 51) received a supplement daily containing 60 mg elemental iron (as NaFeEDTA). The capsules were labelled in red, yellow and blue colour and manufactured by Hurun’s company (a Chinese food‐additive company, Beijing). The intervention lasted 2 months. Women were visited at home once each week by the village nurse to replenish supplements and to monitor compliance by counting and recording the number of supplements that were taken. Setting and health worker cadre: the intervention was performed by village nurses in house visits to the participants in the communities of Shen county, Shandong province, China.
Outcomes	Hb concentration; plasma iron; soluble transferrin receptor; total iron‐binding capacity; MDA; SOD; glutathione peroxidase.
Notes	The participants in the placebo group in this study were given iron supplementation with NaFeEDTA or foods rich in iron, such as the hemachrome‐iron from animal foodstuff, such as meat, fish and sea foods, immediately after the trial. Gestational age at start of supplementation: early gestational age (supplementation started before 20 weeks' gestation). Anaemic status at start of supplementation: anaemic status. Daily iron dose: higher daily dose (60 mg or more elemental iron). Iron release formulation: normal release preparation/unspecified. Iron compound: ferrous sulphate and iron EDTA. Malaria setting: yes. As of 2011: Malaria risk, including P. falciparum malaria, exists in Yunnan and to a lesser extent in Hainan. P. falciparum resistance to chloroquine and sulphadoxine–pyrimethamine reported. Limited risk of P. vivax malaria exists in southern and some central provinces, including Anhui, Ghuizhou, Henan, Hubei, Jiangsu. There is no malaria risk in urban areas.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Individual allocation to groups by order of enrolment.
Allocation concealment (selection bias)	High risk	The capsules were labelled in red, yellow and blue colour and manufactured by Hurun’s company (a Chinese food‐additive company, Beijing).
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Trial participants and the research team were unaware of the treatment assignment. The trial was unblinded after analysis of the primary outcomes.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Trial participants and the research team were unaware of the treatment assignment. The trial was unblinded after analysis of the primary outcomes.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Complete data were available for 147 women, 96.1% of the original number of 153 pregnant women.
Selective reporting (reporting bias)	Unclear risk	There is insufficient information to permit judgement.
Other bias	Low risk	The groups did not differ in age, gestational stage, gravidity, haematological status, levels of MDA, SOD and GSH‐Px at baseline.