Eaves Lauren A, Lodge Evans K, Rohin Wendy R, Roell Kyle R, Manuck Tracy A, Fry Rebecca C
Department of Environmental Sciences & Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
Institute for Environmental Health Solutions, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
J Expo Sci Environ Epidemiol. 2025 Jan 25. doi: 10.1038/s41370-025-00744-8.
Preterm birth (PTB) is a common pregnancy complication associated with significant neonatal morbidity. Prenatal exposure to environmental chemicals, including toxic and/or essential metal(loid)s, may contribute to PTB risk.
We aimed to summarize the epidemiologic evidence of the associations among levels of arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), manganese (Mn), lead (Pb), and zinc (Zn) assessed during the prenatal period and PTB or gestational age at delivery; to assess the quality of the literature and strength of evidence for an effect for each metal; and to provide recommendations for future research.
We adapted the Navigation Guide methodology and followed PRISMA guidelines. We searched the MEDLINE/PubMed database for epidemiologic studies from 1995 to 2023. We used a customized risk of bias protocol and evaluated the sufficiency of evidence for an effect of each metal(loid) on PTB risk.
A total of 1206 studies were identified and screened. Of these, 139 were assessed for eligibility by reading the full-text, and 92 studies were ultimately included (arsenic: 40, cadmium: 30, chromium: 11, copper: 21, mercury: 27, manganese: 17, lead: 41, zinc: 18, metal(loid) mixtures: 12). We found sufficient evidence that lead increases the risk of PTB and, while the evidence was limited, suggestive evidence that cadmium and chromium increase the risk of PTB. The evidence was deemed inadequate to determine an effect for the other metal(loid)s.
Future research would benefit from more precise PTB clinical phenotyping, measuring exposure early and longitudinally throughout pregnancy, using an appropriate media for metal(loid)s under study, and evaluating metal mixtures. Given the strength of evidence linking lead exposure and PTB, active and comprehensive prenatal screening for lead exposure among pregnant individuals is warranted.
By summarizing 92 epidemiologic studies that investigated the associations between metal exposure and preterm birth using the rigorous Navigation Guide methodology, our review provides compelling evidence for a strong link between prenatal lead exposure and preterm birth. Additionally, it suggests potential associations between cadmium and chromium exposure and preterm birth. Given the robust nature of this evidence, there is an urgent need for prenatal screening for lead exposure during pregnancy, along with targeted interventions to reduce exposure. These actions are critical for advancing maternal and child health.
早产是一种常见的妊娠并发症，与新生儿的严重发病情况相关。孕期接触环境化学物质，包括有毒和/或必需的金属（类金属），可能会增加早产风险。
我们旨在总结产前评估的砷（As）、镉（Cd）、铬（Cr）、铜（Cu）、汞（Hg）、锰（Mn）、铅（Pb）和锌（Zn）水平与早产或分娩时孕周之间关联的流行病学证据；评估文献质量以及每种金属产生影响的证据强度；并为未来研究提供建议。
我们采用了导航指南方法并遵循PRISMA指南。我们在MEDLINE/PubMed数据库中检索了1995年至2023年的流行病学研究。我们使用了定制的偏倚风险方案，并评估了每种金属（类金属）对早产风险产生影响的证据充分性。
共识别并筛选了1206项研究。其中，139项通过阅读全文评估其 eligibility，最终纳入92项研究（砷：40项，镉：30项，铬：11项，铜：21项，汞：27项，锰：17项，铅：41项，锌：18项，金属（类金属）混合物：12项）。我们发现有充分证据表明铅会增加早产风险，虽然证据有限，但有提示性证据表明镉和铬会增加早产风险。对于其他金属（类金属），证据被认为不足以确定其影响。
未来的研究将受益于更精确的早产临床表型分析，在整个孕期早期和纵向测量暴露情况，使用适合所研究金属（类金属）的介质，并评估金属混合物。鉴于铅暴露与早产之间证据的强度，对孕妇进行积极全面的产前铅暴露筛查是必要的。
通过使用严格的导航指南方法总结92项调查金属暴露与早产之间关联的流行病学研究，我们的综述为产前铅暴露与早产之间的紧密联系提供了有力证据。此外，它还表明镉和铬暴露与早产之间可能存在关联。鉴于此证据的有力性质，迫切需要在孕期进行产前铅暴露筛查，并采取有针对性的干预措施以减少暴露。这些行动对于促进母婴健康至关重要。
