Milman 1991.

Methods	RCT 2 arms with individual randomisation.
Participants	248 healthy Caucasian Danish women attending birth clinic in Copenhagen, Denmark within 9‐18 weeks of gestation and normal pregnancy. Exclusion criteria: complicated delivery, excessive smoking (> 9 cigarettes/day).
Interventions	Participants were randomly assigned to receive 66 mg of elemental iron (as ferrous fumarate) daily (n = 121) or placebo (n = 127) until delivery. Supplementation started at 8‐9th week until delivery. Setting and health worker cadre: the intervention was performed by obstetricians at the Birth Clinic of the Department of Obstetrics, Herning Hospital in Copenhagen, Denmark.
Outcomes	Maternal: Hb, HCT, erythrocyte indices, iron status, serum ferritin, serum transferrin saturation, serum erythropoietin at baseline and every 4th week until delivery, and 1‐8 weeks after delivery in subsample; pregnancy complications. Infant: birthweight, serum ferritin, transferrin saturation and serum erythropoietin in umbilical cord.
Notes	Unsupervised. Of the 248 women, 20 placebo and 21 iron treated were excluded by the authors in some of the analysis for the following reasons: withdrawn consent, 10; uterine bleeding episodes, 5; placental insufficiency, placenta praevia and abruptio placenta, 7; pre‐eclampsia, 3; partus prematurus, 5; excessive smoking, 3. Sample size has been adjusted for ITT. Compliance: number of tablets consumed was 159 +/‐ 38 and 93 +/‐ 43 tablets in the iron treated and placebo groups respectively. Gestational age at start of supplementation: early gestational age (less than 20 weeks' gestation at the start of supplementation). Anaemic status at start of supplementation: mixed anaemia status at baseline. Daily iron dose: higher daily dose (60 mg or more of elemental iron daily). Iron release formulation: normal release preparation/unspecified. Iron compound: ferrous fumarate. Malaria setting: non‐malarial setting. As of 2011: Malaria: no risk.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not described.
Allocation concealment (selection bias)	Unclear risk	Not described.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Described as double‐blind, placebo‐controlled trial. Not clear whether blinding was effective, there was a major disparity in the number of tablets consumed by women in the active treatment and placebo groups (means 159 vs 93).
Blinding of outcome assessment (detection bias) All outcomes	Low risk	For laboratory outcomes the impact of blinding on outcomes was likely to be small.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Less than 20% lost to follow‐up.
Selective reporting (reporting bias)	Unclear risk	There is insufficient information to permit judgement.
Other bias	Unclear risk	No other bias apparent.