Van Eijk 1978.

Methods	RCT, 2 arms with individual randomisation.
Participants	30 pregnant women with uncomplicated pregnancies and deliveries attending antenatal care clinic at the University Hospital Obstetric Unit in Rotterdam, Netherlands.
Interventions	Participants received 100 mg of elemental iron (as ferrous sulphate) daily or no treatment from the third month of gestation until delivery. Follow‐up was until 12 weeks after delivery. Setting and health worker cadre: the intervention was performed by physicians at the Univeristy Hospital Obstetrical Clinic in Rotterdam, the Netherlands.
Outcomes	Maternal: Hb concentration, serum iron, serum ferritin, transferrin concentration at baseline and every 3‐4 weeks until delivery, and 3 months after delivery. Infant: Hb concentration, transferrin, serum iron, serum ferritin in cord blood at term.
Notes	Unsupervised. Compliance not reported. Gestational age at start of supplementation: early gestational age (supplementation started before 20 weeks' gestation). Anaemic status at start of supplementation: mixed/unspecified anaemia status. Daily iron dose: higher daily dose (more than 60 mg elemental iron daily). Iron release formulation: normal release preparation/unspecified. Iron compound: ferrous sulphate. 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)	High risk	Not used.
Blinding of participants and personnel (performance bias) All outcomes	High risk	No blinding.
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.