The association between maternal cadmium exposure and small for gestational age: a systematic review and meta-analysis

Several observational studies have found an association between maternal Cadmium (Cd) exposure and Small for Gestational Age (SGA). However, these findings are inconsistent. We conducted this meta-analysis to evaluate the relationship between maternal cadmium exposure and SGA risk. A comprehensive search was performed through PubMed, Scopus, Embase, Web of Science, Cochrane Library and OpenGrey to retrieve all pertinent studies published before October 2020. A combined odds ratio (OR) and corresponding 95% confidence interval (CI) were employed to examine this correlation. As a result, nine eligible studies met the inclusion criteria and were included in a systematic review, of those six studies containing sample type of blood were included in meta-analysis, and present meta-analysis showed that maternal cadmium exposure increased the risk of SGA 1.31 times (OR = 1.31; 95% CI = 1.16-1.47 for highest versus lowest category of cadmium). This meta-analysis suggests that maternal Cd exposure may be a risk factor for SGA. However, large prospective studies from different ethnic populations with consideration of other influencing parameters are needed to confirm this finding.