Toxic hazards of fetal toxicants

Of the 287 different chemicals found in the EWG study, 4 are particularly noteworthy for the effects they bring about in later life. These chemicals are dioxin, methyl mercury, PCBs, and DDE, the metabolite of the pesticide DDT. 

Dioxin exposures during fetal development have been associated with endocrine-related cancers (breast and uterine) in women. Dioxin exposure in utero has also been tied to male reproductive effects. Men who are exposed in utero father more than twice as many girls as boys. Dioxin exposure in utero is also associated with infant death and birth defects. 

PCB exposure in the womb is associated with lower IQ scores in children and with abnormal menstrual cycles in women. 

Methyl mercury exposure in utero is associated with reduced brain function and a doubling of the risk of heart attacks and other cardiovascular problems. 

the long-lived metabolite of DDT is associated with premature birth and low birth weight. Low birth weight is considered an indicator of hypertension, cardiovascular disease, and the onset of type II diabetes later in life. 

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Toxic Hazards of Fetal Toxicants 489 Air Pollution 491 Water Pollution 491 Food 491... 

Regulatory guidelines require that there be maternal toxicity at the highest dosage level in embryo-fetal developmental toxicity studies. It is important to avoid excessive toxicity in these studies since it is known that marked maternal toxicity can cause secondary developmental toxicity (see discussion in Section 8.4.3, Association between Developmental and Maternal Toxicity ). This secondary developmental toxicity is irrelevant to the assessment of the developmental hazard of the test agent and thus simply confounds the interpretation of the data. 

This text contains a series of reviews on the toxic effects of drugs and other compounds, viruses, radiation, and occupational hazards. A chapter on drugs of choice in pregnancy and a section on diagnosis of fetal malformations are included. An online version is available. 

Ideally, a full data set should be available for the hazard assessment of a chemical substance, including animal tests to evaluate the toxicokinetics and the following toxicological properties acute toxicity, irritation, sensitization, toxicity following repeated exposure to the substance, mutagenicity and genotoxicify, carcinogenicity, and effects on fertility and fetal development. 

Restricting women of childbearing age from the lead industry workforce for most of the twentieth century because of concerns about fetal exposures and toxic hazards to prenatal populations clearly reduced the prevalence and incidence of reproductive and developmental toxicity. Paternal exposures to lead in terms of reproductive competence indices has continued, based on occupational epidemiology data from several databases. 

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