A systematic review of effect of prenatal zinc supplementation on birthweight,meta-analysis of 17 randomized controlled trials

The effect of prenatal zinc supplementation on birthweight is controversial as randomized controlled trials (rcts) report conflicting conclusions. a systematic review which includes meta-analysis was done on 17 rcts conducted worldwide since,1984 to assess the effect of prenatal zinc supplementation on birthweight. the studies were identified through web-based search. heterogeneity among studies was assessed using cochrane q test statistic. effect-size was measured based on standardized mean difference. pooled effect-size was computed using a variant of random effect model. thirteen of the 17 rcts found no association,three reported positive association,and one reported negative association. based on fixed and random effect models,the pooled effect-sizes were 0.0268 [95% confidence interval (ci) 0.0764,-0.0229) and 0.0712 (95% ci 0.1619,-0.0194) respectively. the effect-size estimate remains insignificant after stratification was made based on the dose of supplementation (optimal vs high dose),type of study (community vs institution-based),and type of source country (developed vs developing). the meta-analysis did not witness any association between birthweight and prenatal zinc supplementation. © international centre for diarrhoeal disease research,bangladesh.