Lui 2013

Methods	This was a double ‐blind randomised controlled trial conducted in five rural counties in Hebei Provinve, China. Women were enrolled from May 2006 to April 2009.
Participants	Pregnant women who recorded dates of their menstruation for 2 or more months before they became pregnant, were nulliparous, at least 20 years old, not more than 20 weeks' gestation, legally competent, had not consumed micronutrient supplements other than folic acid in the prior 6 months, had a Hb level greater than 10.0 g/dL, resided in and received prenatal care in 1 of 5 counties, and consented to participate were eligible. 18,775 pregnant women with singleton pregnancies were randomised to group A (n = 6261), group B (n = 6252), and group C (n = 6262).
Interventions	The study has 3 arms. Group A received folic acid 400 μg, group B received folic acid 400 μg and iron 30 mg, and group C received the UNICEF formulation containing folic acid 400 μg, Fe 30 mg, vitamin A 800 μg, E 10 mg, D 5 mcg, C 70 mg, B1 1.4 mg, B2 1.4 mg, B6 1.9 mg, B12 2.6 μg, niacin 18 mg, Zn 15 mg, Cu 2 mg, iodine 150 μg, selenium 65 μg. Supplements were take from enrolment until delivery.
Outcomes	Perinatal mortality, neonatal mortality, infant mortality, maternal Hb and anaemia at 24 to 28 weeks of gestation, gestational age at birth, preterm birth, LBW, birthweight, low weight for height, low weight for age, low height for age, infant anaemia, gastrointestinal side‐effects (nausea, vomiting, or other mild gastrointestinal discomfort) at monthly visits.
Notes	There were no significant differences at baseline between the groups Data for side‐effects: 6% (n = 355) in the MMN group while 3.6% (n = 212) in the iron folic acid group. We used the estimates for the comparison of MMN vs. IFA groups in this review.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "A statistician external to the study randomly assigned ten 4‐digit lot numbers to each of the 3 supplement types (masked to the formulation and allocation) and generated the assignment list for each county proportional to the expected number of participants; within each county and block, lot numbers were randomly assigned using RANUNI in SAS statistics software (SAS Institute Inc)". Comment: probably done.
Allocation concealment (selection bias)	Low risk	Quote: " A statistician external to the study randomly assigned ten 4‐digit lot numbers to each of the 3 supplement types (masked to the formulation and allocation)". Comment: probably done.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Attrition rate (6.2%) was less than 20% and reasons for attrition and exclusions were provided.
Selective reporting (reporting bias)	Low risk	Comment: all outcomes mentioned were reported.
Other bias	Low risk	Comment: no other bias was identified.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "Aside from a pharmaceutical engineer who ensured allocation of lot numbers to the correct supplement formulations, all others (i.e., participants, local physicians, study personnel, and investigators) were masked to the identity of the supplements". Comment: probably done.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "Treatment codes were broken after completion of the study and main analyses.", " double blind". Comment: probably done.