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.

Association between maternal cadmium exposure and preterm birth: a meta-analysis.

The association between Cadmium and the risk of preterm birth (PTB) has remained controversial. A number of studies found a positive correlation between maternal Cd exposure and PTB; however, there are conflicting reports about this correlation. Therefore, herein we performed this meta-analysis to examine the association between maternal Cd exposure and the risk of PTB.A systematic search was conducted through PubMed, Scopus, Embase and OpenGrey from inception to May 2020 to find all eligible studies. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were used to examine this correlation. A random-effects model was applied in this meta-analysis due to significant statistical heterogeneity among included studies.Overall, 10 eligible studies met the inclusion criteria and were included in our analysis, and results of the present meta-analysis indicated that maternal cadmium exposure is associated with the risk of PTB (OR = 1.32; 95% CI = 1.08-1.61).This meta-analysis suggests that maternal Cd exposure might be associated with the risk of PTB. Yet, large prospective studies from different ethnic populations which consider other influencing parameters are still required to confirm this finding.

Association of maternal lead exposure with the risk of preterm: a meta-analysis.

BACKGROUND: The relationship between maternal lead level and risk of preterm birth (PTB) remained controversial. Therefore, herein we performed this meta-analysis to investigate the association of maternal blood, urine and cord blood lead level with the risk of PTB using observational studies. METHODS: A systematic search was conducted in PubMed, EMBASE and Ovid Medline databases from inception to August 2019, and sixteen studies with 65600 participants investigating the association between maternal lead level and PTB were included in our meta-analysis. Odds ratios (ORs) and 95% confidence intervals (95% CI) were calculated for the highest versus lowest lead level by random-effects model. RESULTS: Overall, the pooled OR of all included articles for the highest versus lowest PTB score was 1.29 (95% CI = 1.14-1.46; I2 = 80.4%, p < .001), and the results revealed a direct and significant relationship between second and third trimester blood lead level (BLL) and PTB (OR 2nd trimester= 1.61, 95% CI = 1.08-2.40, OR 3rd trimester= 1.57, 95% CI = 1.11-2.23). CONCLUSION: Results of this meta-analysis showed that maternal BLL is directly associated with the risk of PTB.