Ramakrishnan 2003.

Methods	This RCT was carried out in Mexico Dates of study: 1997‐2000
Participants	Pregnant women who were < 13 weeks' pregnant, were not receiving MMN supplementation and who agreed to participate were included in the study. A total of 873 women were randomised into the MMN group (n = 435, mean age 23.09 ± 5.48) and the iron‐only group (n = 438, mean age 23.00 ± 5.08).
Interventions	MMN group: tablets included the following vitamins and minerals: iron 60 mg as ferrous sulphate, folic acid 215 mcg, vitamin A 2150 IU, vitamin D3 309 IU, vitamin E 5.73 IU, thiamin 0.93 mg, riboflavin 1.87 mg, niacin 15.5 mg, vitamin B6 1.94 mg, vitamin B12 2.04 mcg, vitamin C 66.5 mg, zinc 12.9 mg, magnesium 252 mg Control group: given iron‐only tablets with 60 mg of iron as iron sulphate All were given orally, from recruitment 6 days a week until delivery.
Outcomes	Preterm births (< 37 weeks of gestation), SGA (below the 10th percentile for birthweight‐for‐gestational age), LBW (< 2500 g), perinatal mortality, mean Hb concentration, mean serum ferritin It should be noted that the data for SGA were obtained from a separate report (Food and Nutrition Bulletin 2009) and not from the individual trial report.
Notes	Data on birth outcomes were only available for 656 pregnancies (MMN group n = 328 and control group, iron only n = 326). The 2 groups did not differ significantly in most of the characteristics at recruitment, except for marital status (more single mothers in MMN supplementation group) and mean BMI (significantly lower in the MMN supplementation group). Declarations of interest: the trial authors declared no conflict of interest. Funding sources: Thrasher Research Fund, United Nations Children's Fund (UNICEF) New York, Conacyt, and the Instituto Nacional de Salud Pública, Mexico
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Randomization was carried out by using 4 color‐coded groups (2 per treatment) that were assigned a priori with the use of a computer‐generated list". Comment: probably done.
Allocation concealment (selection bias)	Low risk	Quote: "Four colors were used to ensure masking and were assigned at random before the study began to a list of serial numbers from 1 to 1000" and "pregnant women were allocated to the pre‐assigned color code as they were added to this list at the time of recruitment". Comment: probably done.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "All study personnel and investigators were blinded to the group assignment, the details of which were kept at Emory University and the INSP in sealed envelopes that were opened only after preliminary data analysis was completed". Comment: participants and caregivers were probably blinded to the treatment assignment.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "All study personnel and investigators were blinded to the group assignment, the details of which were kept at Emory University and the INSP in sealed envelopes that were opened only after preliminary data analysis was completed". Comment: outcome assessors were probably blinded to the treatment assignment.
Incomplete outcome data (attrition bias) All outcomes	High risk	Exclusion was 5.2% but reasons for it were not reported. Attrition (26.2%) along with their reasons were reported.
Selective reporting (reporting bias)	Low risk	Comment: all outcomes mentioned in the methods section were presented in the various publications of this trial.
Other bias	Low risk	Comment: no other bias was identified.