Pregnancy teratogenic chemicals

A variety of cell-based and animal-based studies can be performed to ensure that a new chemical does not cause reproductive or developmental effects. A battery of tests is done to ensure that there are no harmful effects on fertility. Teratogenicity studies are performed to ensure that the chemical does not cause physical malformations in the offspring from exposure during pregnancy. Multiple generations of animals may be continuously exposed to ensure that a compound is safe. 

Most drugs and chemicals pose a threat to the developing fetus. An estimated 4 to 5% of developmental defects in humans result from prenatal exposure to drugs or environmental chemicals. This is particularly important, since women with irregular menstrual cycles may be exposed to teratogens and enter the sensitive period of organogenesis before pregnancy is suspected. 

Teratogenic agents may be drugs taken during pregnancy radiation, both ionizing and nonionizing environmental pollutants chemical hazards in the workplace dietary deficiencies and natural contaminants. 

Flucytosine is teratogenic in rats, and its close chemical relation to antimetabolites plus the fact that 5-fluorouracil is a metabolite make it inadvisable to administer flucytosine during pregnancy or to fertile women taking no contraceptive precautions. 

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