Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry, University of Western Ontario, Ontario, Canada.
Ther Drug Monit. 2009 Dec;31(6):670-82. doi: 10.1097/FTD.0b013e3181bb0ea1.
Methylmercury is an environmental pollutant that can cause irreversible effects on the development of children. Although there is no doubt that high exposure can cause neurodevelopmental deficits, the threshold that will adversely affect the developing fetus is not well defined. Our objective was to systematically review the evidence of neurodevelopmental risks of methylmercury to the unborn child from maternal fish consumption to define the lowest observable adverse effect hair concentration (LOAEHC).
A systematic review was conducted of all original research reporting on the effects of methylmercury on the human fetus. A literature search was undertaken using SCOPUS, Medline-Ovid, PubMed, Google Scholar, and EMBASE. Papers were selected based on the following inclusion criteria: 1) child neurodevelopmental outcome; 2) comparison groups; and 3) methylmercury exposure through fish consumption.
Forty-eight publications met these inclusion criteria. Thirty articles reported on longitudinal studies and 18 were cross-sectional studies. Variations in study design precluded formal meta-analysis. Based on an evaluation of these studies, we defined the LOAEHC at 0.3 microg/g of maternal hair mercury. The longitudinal studies yielded a LOAEHC of 0.5 microg/g.
In the clinical context, the majority of pregnant women consume mercury-containing fish in amounts that are lower than the LOAEHC defined in this study. However, the LOAEHC is in the same order of magnitude of mercury exposure that occurs in significant numbers of women. Hence, although it appears safe to suggest that eating the recommended types and amounts of fish poses no measurable risks for neurodevelopmental deficits, analysis of hair mercury content before pregnancy might be suggested because dietary modification can decrease body content and risk.
甲基汞是一种环境污染物，可对儿童发育造成不可逆的影响。虽然高暴露量无疑会导致神经发育缺陷，但对发育中的胎儿产生不利影响的阈值尚未明确界定。我们的目的是系统地审查母体鱼类消费导致胎儿甲基汞的神经发育风险的证据，以确定可观察到的最低不良效应毛发浓度（LOAEHC）。
对所有报告甲基汞对人类胎儿影响的原始研究进行了系统审查。使用 SCOPUS、Medline-Ovid、PubMed、Google Scholar 和 EMBASE 进行了文献检索。根据以下纳入标准选择论文：1）儿童神经发育结果；2）比较组；3）通过鱼类消费暴露于甲基汞。
有 48 篇出版物符合这些纳入标准。30 篇文章报告了纵向研究，18 篇是横断面研究。研究设计的差异排除了正式的荟萃分析。基于对这些研究的评估，我们将 LOAEHC 定义为 0.3 微克/克母体毛发汞。纵向研究得出的 LOAEHC 为 0.5 微克/克。
在临床环境中，大多数孕妇食用的含汞鱼类数量低于本研究中定义的 LOAEHC。然而，LOAEHC 与大量女性发生的汞暴露量处于同一数量级。因此，尽管建议食用推荐类型和数量的鱼类不会对神经发育缺陷造成可衡量的风险似乎是安全的，但在怀孕前分析头发中的汞含量可能是合理的，因为饮食的改变可以减少体内的汞含量和风险。
