Increased incidence of spontaneous abortions on exposure to cadmium and lead: a systematic review and meta-analysis

Abstract

Background

Spontaneous abortions are the most severe complication of early pregnancy and are a major reproductive health problem. Although this could be caused due to various cytogenetic, immunological, or endocrinological reasons, role of environmental toxicants cannot be ruled out. In order to explore the role of cadmium and lead in causing spontaneous abortions, current systematic review and meta-analysis had been carried out.

Methodology

Literature search was performed using appropriate keywords in PubMed, Science Direct, Cochrane Library, and Google Scholar databases up to December 25 2020 according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (PRISMA). Metananalysis was carried out with the help of RevMan software (version 5.3).

Results

Meta-analysis of nine studies on cadmium concentrations in blood of women with at least one spontaneous abortions and controls revealed standardized mean difference (SMD)=3.39, 95% CI (2.17, 4.61), with p < .05. Similarly, meta-analysis of eight studies on lead concentrations revealed standardized mean difference (SMD)=6.24, 95% CI (4.34, 8.14), with p < .05.

Conclusion

Populations exposed to heavy metals such as cadmium and lead are at higher risk of pregnancy loss. Therefore, couples experiencing repeated pregnancy losses may be screened for heavy metal load.

暴露于镉和铅自然流产发生率增加：系统评价和荟萃分析 摘要

背景：自然流产是早孕最严重的并发症, 是主要的生殖健康问题。虽然这可能是由于各种细胞遗传学、免疫学或内分泌学原因引起的, 但不能排除环境毒物的作用。为了探讨镉和铅在导致自然流产中的作用, 本文进行了系统评价和荟萃分析。

方法：根据系统综述和荟萃分析的首选报告项目（PRISMA）, 使用适当关键字在PubMed, Science Direct, Cochrane图书馆和Google学术数据库中的检索截至2020年12月25日之前文献, RevMan软件（版本5.3）进行了荟萃分析。

结果：对至少一次自然流产和对照组妇女血液中镉浓度的九项研究进行的荟萃分析显示, 标准化均数差（SMD）=3.39, 95%CI（2.17, 4.61）, p < 0.05。同样, 对八项铅浓度研究的荟萃分析显示, 标准化均数差（SMD）=6.24, 95%CI（4.34, 8.14）, p < 0.05。

结论：暴露于镉和铅等重金属的人群妊娠丢失的风险更高。因此, 反复流产的夫妇可能会被筛查出重的金属超标。

Keywords:

• Cadmium (Cd)
• lead (Pb)
• spontaneous abortions
• toxicity
• systematic review
• meta-analysis

Disclosure statement

The authors declare that they have no competing interests.

Acknowledgement

The project is supported by Indian Council of Medical Research (ICMR), New Delhi vide grant number 2020-9200.