Christian 2003 (C).

Methods	Cluster‐randomised trial with 5 treatment arms.
Participants	4998 married pregnant women (with positive pregnancy test) living in the south eastern plains district of Sarlahi, Nepal. Widows were excluded.
Interventions	Participants were randomly assigned to 1 of 5 groups: group 1 received 1000 μg retinol equivalents vitamin A (control) daily; group 2 received 1000 μg retinol equivalents vitamin A and 400 μg (0.4 mg) folic acid daily; group 3 received 1000 μg retinol equivalents vitamin A, 400 μg (0.4 mg) folic acid and 60 mg elemental iron (as ferrous fumarate) daily; group 4 received 1000 μg retinol equivalents vitamin A, 400 μg (0.4 mg) folic acid, 60 mg of elemental iron (as ferrous fumarate) and 30 mg of zinc sulphate daily; group 5 received 1000 μg retinol equivalents vitamin A, 400 μg (0.4 mg) folic acid, 60 mg elemental iron (as ferrous fumarate), 30 mg of zinc, 10 μg vitamin D, 10 mg vitamin E, 1.6 mg thiamine, 1.8 mg riboflavin, 20 mg niacin, 2.2 mg vitamin B6, 2.6 μg vitamin B12, 100 mg vitamin C, 65 μg vitamin K, 2 mg cooper, and 100 mg magnesium daily. Only groups 1, 2 and 3 are considered in this review. Supplementation started at recruitment and continued until 3 months postpartum in the case of live births of 5 weeks or more after a miscarriage or stillbirth. All participating women were offered deworming treatment (albendazole 400 mg single dose) in the second and third trimester. Supplementation lasted 257.5 days in group 1 (control) and 251.7 days in the group 3 receiving vitamin A, iron and folic acid. Comparisons: group 3 vs group 1: effect of iron supplementation with folic acid; group 3 vs group 2: effect of iron supplementation alone. Setting and health worker cadre: the intervention was performed by community health workers in the home of the participants in remote villages in Sarlahi, Nepal. In Nepal, 8% of women received assistance from an auxiliary nurse midwife or doctor. Dosing and supplement replenishment was done by 426 local female workers, 1 per sector, or about 40 households.
Outcomes	Maternal: premature delivery, Hb and iron status at baseline in the third trimester (scheduled at 32 week of gestation) and Hb at 6 weeks postpartum, prevalence of anaemia in third trimester and at 6‐week postpartum, severe anaemia postpartum, moderate anaemia during third trimester, moderate anaemia postpartum, moderate high Hb concentrations during third trimester Infant: birthweight, prevalence of low birthweight, perinatal mortality, neonatal mortality, infant deaths, small‐for‐gestational age.
Notes	Supplementation with 1000 μg retinol equivalents vitamin A (control) daily and deworming treatment (albendazole 400 mg single dose) in the second and third trimester at were co‐interventions for purposes of the analysis. Unsupervised but trial personnel visited women twice each week to monitor supplement intake. Compliance during pregnancy measured by pill count was high (median 88%) and did not vary by groups. 98% of the women accepted the albendazole treatment at both times (second and third trimesters). Approximate 50% of women started supplementation before 9 weeks of gestational age. Gestational age at start of supplementation: early gestational age (supplementation started before 20 weeks' gestation). Anaemic status at start of supplementation:unspecified/mixed anaemia status. Daily iron dose: higher daily dose (60 mg or more elemental iron). Iron release formulation: normal release preparation/not specified. Iron compound: ferrous fumarate. Malaria setting: yes. As of 2011: Malaria risk due predominantly to P. vivax exists throughout the year in rural areas of the 20 Terai districts bordering India, with occasional outbreaks of P. falciparum from July to October inclusive. Seasonal transmission of P. vivax takes place in 45 districts of the inner Terai and mid hills. P. falciparum resistant to chloroquine and sulphadoxine–pyrimethamine reported.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Cluster‐randomisation. No evidence of recruitment bias. Participants did not know beforehand which cluster they were in.
Allocation concealment (selection bias)	Low risk	Coded.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	This was described as a double‐blind trial. It was reported that the study supplements were identical in appearance and women, staff, investigators and statisticians were not aware of supplement codes until the end of the study.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Field staff and investigators were blinded.
Incomplete outcome data (attrition bias) All outcomes	High risk	More than 20% losses to follow‐up.
Selective reporting (reporting bias)	Unclear risk	There is insufficient information to permit judgement.
Other bias	Low risk	This was a cluster‐randomised trial, baseline characteristics did not differ by treatment group in age at baseline, SES, parity, gestational age at enrolment, previous miscarriage. The level of compliance did not differ by groups. Analysis was adjusted for cluster‐design effect.