Goshtasebi 2012.

Methods	Quasi‐RCT, 2‐arm trial.
Participants	370 non‐anaemic pregnant women aged 18‐35 with singleton pregnancy, parity < 4 and normal BMI. gestational age 14–20 wks, and no history of high‐risk pregnancy, smoking or drug abuse, in Teheran, Iran between February and November 2009. Exclusion criteria: Hb less than 105 g/L, preterm delivery before wk 34, any condition that needs medical or surgical intervention.
Interventions	Participants were randomly assigned to 1 of 2 groups: .group 1 received 1 tablet containing 50 mg elemental iron (as ferrous sulphate) and 1 tablet containing 1000 µg (1 mg) folic acid tablet per day, since 20th gestational wk until delivery; group 2 received 1 tablet containing 50 mg elemental iron (as ferrous sulphate) and 1 tablet containing 1000 µg (1 mg) folic acid twice a wk on Mondays and Thursdays, since 20th gestational wk until delivery. All mothers took also part in an educational programme on nutrition in pregnancy as co‐intervention. Setting and health worker cadre: prenatal clinic of the Imam Hospital, Sari, Islamic Republic of Iran. Mothers of both groups received routine care and were followed up until delivery. The health worker who provided the tablets is not specified.
Outcomes	Hb and ferritin in cord blood, birthweight, anaemia indices and side effects in mother during pregnancy. Laboratory method for ferritin concentration: RIA (Gamma Counter System, Kontron).
Notes	1. By gestational age: early (supplementation started before 20 wks' gestation or prior to pregnancy). 2. By anaemia status at baseline: non‐anaemic (Hb 110 g/L or above during first and third trimesters or Hb 105 g/L or above if in second trimester) at start of supplementation. 3. By weekly iron dose in the group receiving intermittent supplementation: low weekly dose of iron in the intermittent group (120 mg elemental iron or less per wk). 4. By release speed of iron supplements: not specified/unreported/unknown. 5. By bioavailability of the iron compound relative to ferrous sulphate: equivalent or lower: ferrous sulphate. 6. By intermittent iron supplementation regimen: other intermittent regimens (twice a wk). 7. By malaria endemicity of the area in which the trial was conducted: not specified/unreported/unknown. Source of funding: Tarbiat Modares University research office, Iran as part of a Midwifery Master of Science dissertation.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Reported as random but method not reported.
Allocation concealment (selection bias)	High risk	Without blinding, random allocation was done according to the day of wk a pregnant woman attended the clinic: clients on even days were assigned to the daily group and attendees on odd days were allocated to the twice‐weekly group.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Reported as open trial. Participants and personnel knew which intervention a participant received.
Blinding of outcome assessment (detection bias) Laboratory outcomes	Low risk	Lack of blinding would be unlikely to affect laboratory outcomes.
Blinding of outcome assessment (detection bias) Side effects and compliance	High risk	Reporting of side effects may have been affected by lack of blinding.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Data available for all participants in the study.
Selective reporting (reporting bias)	Low risk	Not apparent. This clinical trial was registered in the Iranian Registry of Clinical Trials (www.irct.ir) with registration number ID: IRCT138802131641N4.
Other bias	High risk	Authors report that due to financial constraints the trial was open and baseline ferritin values were not evaluated for comparability among the groups. Also the supervision on adherence was not done. Supervised directly.