Abortion, lead workers

Lead is known to cause reproductive and developmental toxicity. Decreased sperm counts and abnormal sperm development have been reported in male workers heavily exposed to lead. Increased incidences of spontaneous abortion have been reported in female lead workers as well as in the wives of male lead workers (13). Lead crosses the placenta and has been found to cause irreversible neurologic impairment to the fetus at maternal blood levels as... 

The toxicity of lead to the developing embryo and fetus has been known for centuries. It is an old observation that lead is an abortifacient, and that female lead workers had a high rate of miscarriage (Legge and Goadby, 1912). In a series of 123 cases studied by Paul (1860) there were more than 73 fetal deaths, and of the 50 live births 35 had died by age 3. Later studies noted that abortion and stillbirth rates of lead workers were as high as 60% (Aub et al., 1926). 

Toxic quantities of lead in the human body impact the reproductive processes of both men and women. An increased incidence of spontaneous abortions has been documented in female lead workers and in the wives of male lead workers, i.e. persons working in lead smelting or manufacture of lead containing products. Male lead workers with blood lead concentrations of 53 to 75 ug/dl have been reported to have decreased sperm counts as well as altered morphology of the sperm. [4]. 

Kato and co-workers had much better success in performing unusual 1,3-dipolar cycloadditions with isomunchnones than with munchnones (vide supra). Thus the room temperature union of isomunchnone 383a with benzocyclopropene 271 leads to a syn cycloadduct (Fig. 4.136). The latter is remarkably stable, is recovered unchanged on heating to 300°C, and is impervious to the action of tributylphosphine, in an abortive attempt to excise the bridging oxygen, which would have led to a methanooxonine. 

By the first decade of the twentieth century, recognition of reproductive and prenatal harm and subsequent responses greatly reduced the adverse effects of lead in utero during worker pregnancies through constraints on women of childbearing age in the lead workplace. In particular, the prevalence and incidence of such gross Pb toxicity outcomes as spontaneous abortions, stillbirths, and depressed early natal survival declined markedly. 

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