Tura 1989.

Methods	RCT, 2 arms with individual randomisation.
Participants	254 non‐anaemic non‐iron deficient healthy pregnant women from multiple centres in Italy between 12‐16 weeks of gestation. Exclusion criteria: acquired or congenital anaemia, haemoglobinopathies, thalassaemia, medically or surgically treated cardiopathy, abortion, hypertension, gastric resection, metabolic or endocrine disorder, hepatic or renal disease, epilepsy or another neurological disease, previously treated for cancer, alcohol or substance dependence.
Interventions	Participants were randomly assigned to receive 40 mg of elemental iron (containing 250 g of ferritin in a micro granulated gastric‐resistant capsule) daily or no treatment from 12‐16 weeks of gestation until the end of puerperium. Setting and health worker cadre: the intervention was performed by physicians in health centres in Italy.
Outcomes	Maternal: Hb concentration, RBC count, MCV, serum iron, total transferrin, transferrin saturation, serum ferritin at 12‐16 weeks, 2 times during pregnancy, at 38‐42 weeks, and at puerperium 48‐52 weeks.
Notes	Unsupervised. The study included another sample of women who were iron deficient and received 2 forms of iron preparation. This sample is not used in this review. Compliance reported as higher than 98.5%. Gestational age at start of supplementation: early gestational age (supplementation started before 20 weeks' gestation). Anaemic status at start of supplementation: non‐anaemic. Daily iron dose: medium iron dose (more than 30 and less than 60 mg). Iron release formulation: micro granulated gastric resistant capsule. Iron compound: not specified. 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)	Low risk	By random number lists.
Allocation concealment (selection bias)	Low risk	Sealed envelopes progressively numbered.
Blinding of participants and personnel (performance bias) All outcomes	High risk	No mention of blinding. No placebo.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Low risk for laboratory outcomes.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Less than 20% loss to follow‐up.
Selective reporting (reporting bias)	Unclear risk	There is insufficient information to permit judgement.
Other bias	Unclear risk	No other bias apparent.