We identified 115 potentially relevant articles for detailed review (Figure
1). We excluded 51 articles during initial screening because they were not directly referring the effect of micronutrients on pregnancy. The remaining 64 articles were again analyzed for their internal consistency with the research objectives and some 47 of them were found not relevant and/or incomplete, hence excluded for the second time. The remaining 17 of were considered for final review and analysis. From these finally accommodated articles, five of them were related to the effect of Calcium and vitamin D supplementation, three of them were about Iron and iron folic acid supplementation, and the remaining majority
 articles reviewed were about the effects of MMN supplementations on pregnancy and its outcomes.
Though some degrees of variation by type and amount of micronutrients supplied are observed, the results of the final analysis of the most articles reviewed, favored the supplementation of micronutrients to pregnant mothers.
The systematic review of clinical trials by Buppasiri P et al. from Thailand, with the objective of determining the effect of calcium supplementation on maternal, fetal and neonatal outcomes revealed that Calcium supplementation is associated with a significant protective benefit in the prevention of pre-eclampsia and improving mean infant birth weight. The same study also confirmed lack of additional benefits for calcium supplementation in prevention of preterm birth or low infant birth weight
Another study with a similar finding by Hofmeyr GJ et al. concluded that Calcium supplementation appears to almost halve the risk of pre-eclampsia, and to reduce the rare occurrence of the composite outcome ‘death or serious morbidity’, with no other clear benefits, or harms
The thesis based study by Melody B. on maternal vitamin D status during pregnancy as a predictor of offspring bone mass at three years of age shows that maternal vitamin D status during pregnancy did not predict for the child at 3 years of age
. Another systematic review by Bruce W. on dietary vitamin D requirements during pregnancy and lactation recommends further studies to determine optimal vitamin D intakes for pregnant and lactating women as a function of latitude and race
Similarly, the study by Dror DK et al. shows the existence of recent evidence supporting the role of maternal vitamin D status, particularly early in pregnancy, in modulating the risk of pregnancy complications and in sustaining fetal growth, bone development, and immune maturation
On the other hand, according to the findings of the many of the final articles reviewed; though few disfavored the beneficial outcomes of supplementing MMN to pregnant mothers; majority of the others in one way or another supported the presence of significant association and benefit of MMN supplementation with at least one birth outcome.
Among the studies against the added role of supplying MMN to pregnant mothers, the study by Parul Christian, which was about the Effects of alternative maternal micronutrient supplements on low birth weight in rural Nepal, revealed that Antenatal folic acid-iron supplements modestly reduce the risk of low birth weight but MMN confer no additional benefit over folic acid-iron in reducing this risk
[17, 18]. Another Indian study by Umesh Kapil et al. also said MMN Supplements will not Reduce Incidence of Low Birth weight and other pregnancy outcomes
. The Hungarian RCT study by Czeizel AE also revealed that Periconceptional multivitamin supplementation increased fertility but had no significant effect on the rate of different groups of fetal deaths, low birth weight and preterm birth in singletons
Conversely, the remaining RCT and observational studies reviewed from various parts of the world confer that oral supplementation of MMN for pregnant woman benefits the mother and the growing fetus as well as the newborn.
In line with this, the reviews and RCT studies by Prakesh S., Zulfiqar A Bhutta, Michael B Zimmermann and other scholars across the globe unanimously reported that supplementing pregnant mothers with MMN immensely benefits both the mother and the growing fetus in reducing maternal morbidity conditions and morbid neonatal birth outcomes
Similarly, the systematic review by Prakesh S. et al. also indicates that prenatal MMN supplementation is associated with a significantly reduced risk of low birth weight and with improved birth weight when compared with iron–folic acid supplementation. However, there was no significant effect of MMN supplementation on the risk of preterm birth or small-for-gestational-age infants
Additionally, the review by Zulfiqar A Bhutta et al. also provides evidence on significant benefit of MMN supplementation during pregnancy on reducing SGA births as compared to iron-folate, with no significant increase in the risk of neonatal mortality in populations where skilled birth care is available and majority of births take place in facilities
Furthermore, other review by Kosuke Kawai et al. discusses the safety, efficacy and effective delivery of maternal micronutrient supplementation requiring further research. The other study by Dr. Kathleen Abu-Saad on the other side, declares that maternal nutrition is a modifiable risk factor of public health importance that can be integrated into efforts to prevent adverse birth outcomes, particularly among economically developing/low-income populations
On the other hand, RCT by Philip N Baker et al. revealed that Poor micronutrient intake and status increases the risk of SGA births in pregnant adolescents and hence mothers should get prenatal micronutrient supplementation in addition to the customary iron folic acid supplementation
In addition, in a poor population, the effects of maternal MMN supplementation on the fetus persisted into childhood, with increases in both weight and body size. Maternal MMN supplementation might therefore be an important part of overall strengthening of prenatal-care programmes
Therefore, it is clear to see that given comparability of impacts on maternal anemia, the decision to replace iron-folate with MMN during pregnancy may be taken in the context of available services in health systems and birth outcomes monitored.