STUDY DESIGN

Design:

randomised placebo-controlled trial.

Allocation:

unclear.*

Blinding:

blinded (patients and healthcare providers).*

STUDY QUESTION

Setting:

6 prenatal clinics in Iran.

Patients:

750 non-smoking women 17–35 years of age (mean age 26 y) with a singleton pregnancy in the early second trimester (mean 13 wks), haemoglobin concentration ⩾13.2 (mean 14.0) g/dl, body mass index 19.8–26 kg/m², no history of threatened abortion in the current pregnancy, and no disease related to polycythaemia such as asthma or chronic hypertension.

Intervention:

ferrous sulphate, 150 mg (50 mg of elemental iron) (n = 375), or placebo (n = 375) once daily throughout pregnancy. All women received folic acid, 1 mg/day, but were not allowed to take other vitamin or mineral supplements.

Outcomes:

small for gestational age (SGA, <10th percentile) infant, hypertensive …