Sood 1975

Methods	Trial conducted in New Dehli and Tamil Nadu, India.
Participants	Pregnant women with gestational age 22 ± 2 were eligible to participate in the trial. A total of 647 pregnant women participated in the trial. Women with chronic diseases like heart diseases, tuberculosis, leprosy, chronic diarrhoea and a Hb < 5 g/100 mL were excluded from the study.
Interventions	There were total of 7 study groups. 2 in the control group and 5 in the intervention group. 1 of the control groups received placebo and other received vitamin B12 and folic acid alone. 4 intervention groups received vitamin B12, folic acid and iron in a range of 30 to 240 mg. The fifth intervention group received 120 mg of iron without vitamin B12 and folate. Supplementation was given for 10‐12 weeks.
Outcomes	Outcomes were improvement in maternal Hb/haematocrit, iron absorption from maternal gut, fetal birthweight, maternal and fetal Hb 3 months postpartum, hookworm infestation in mother and side‐effects of supplementation.
Notes	None of the outcomes were reported in a format that allowed inclusion of the data in this review.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "By reference to previously prepared random tables the women were allocated to one of the two streams A or B" and "within each stratum subjects were allotted to final treatment groups according to a set of random numbers". Comment: probably done.
Allocation concealment (selection bias)	High risk	Quote: "By reference to previously prepared random tables the women were allocated to one of the two streams A or B" and "within each stratum subjects were allotted to final treatment groups according to a, set of random numbers". Comment: probably not done.
Incomplete outcome data (attrition bias) All outcomes	High risk	Attrition was 30% and reasons for it were reported.
Selective reporting (reporting bias)	Low risk	Comment: all outcomes mentioned in the methods section were presented in the paper.
Other bias	Low risk	Comment: no other bias was identified.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "All the tablets had the same appearance and had the daily folic acid and iron dose divided into two tablets". Comment: participants, caregivers probably blinded to the treatment assignment.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "All the tablets had the same appearance and had the daily folic acid and iron dose divided into two tablets". Comment: outcome assessors probably blinded to the treatment assignment.