Ghana 2009.

Methods	A double‐blind, RCT.
Participants	400 pregnant women in Ghana earlier than 16 weeks of gestation who presented themselves for antenatal care and have been screened for their gestational age in the Wa Regional Hospital of the Upper West Region in Ghana. Women who were receiving zinc supplements at any dosage level or were severely anaemic (that is, Hb less than 7.0 g/dL) were excluded. The iron‐zinc and iron‐only supplements were pre‐coded and supplied by Nutricaps pharmaceutical company in the United States of America. The supplements (in the form of capsules) were of the same shape, colour and taste and packaging. The women were advised to take the supplements at least 2 hours before or after meals, and at night, just before going to bed. Compliance was monitored by interviewing all participants after having being enrolled for 4 weeks using structured questionnaire to check the frequency and dosage of supplement intake. A subsample of 213 women at recruitment were assessed for serum ferritin but only 173 were repeated at 34‐36 weeks' gestation. N = 299 for intervention and n = 301 for control allocated. 27 out of 299 of the intervention group and 30 out of 301 of the control group were lost to follow‐up and excluded from the analysis.
Interventions	Women received a combined supplement of 40 mg zinc as zinc gluconate and 40 mg iron as ferrous sulphate and women in the control group received 40 mg elemental iron as ferrous sulphate without zinc content. Both groups received malaria chemoprophylaxis in the form of sulphadoxine pyrimethamine, and 400 μg folic acid. The supplements were taken every other day from enrolment until delivery. Intervention group: 40 mg zinc plus 40 mg iron (n = 299). Control group: 40 mg iron only (n = 301).
Outcomes	Intrauterine growth restriction/small‐for‐gestational age; low birthweight; preterm birth; birthweight; haemoglobin concentration; serum ferritin concentration; plasma zinc concentration.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	By computer‐generated random number.
Allocation concealment (selection bias)	Unclear risk	Opaque envelopes.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	The capsules for both intervention and placebo were the same.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No description.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	27 out of 299 of the intervention group and 30 out of 301 of the control group were lost to follow‐up and excluded from the analysis.
Selective reporting (reporting bias)	Unclear risk	It was not clear if a protocol of this trial had been published prior to the study; no maternal outcomes reported.
Other bias	Low risk	Baseline characteristics were compared, with no significant difference seen between groups.