A Cochrane review included 15 trials in low or middle-income countries. When compared with iron and folate supplementation , MMS decreased the number of low birthweight babies (RR 0.88, 95% CI 0.85 to 0.91), small-for-gestational-age babies (RR 0.90, 95% CI 0.83 to 0.97). No statistically significant differences were shown for the outcomes of preterm births and perinatal mortality, or maternal mortality in any of the comparisons.
Comment: The quality of evidence is downgraded by study quality (unclear allocation concealment in half of the studies).