Reproductive hazard, definition

The studies described herein are considered the most definitive currently available for the assessment of developmental and reproductive hazard. The maternal animals in these studies represent the best and most practical model of the human in terms of complexity. 

The February 1987 update of the October 1985 RTECS list of chemicals which cause reproductive hazards, had 6,917 entries. We selected the following T codes T01-T09 (paternal effects), T25 (postimplantation mortality), T31-T59 (effects on embryo or fetus, and specific developmental abnormalities), and T65 (transplacental tumorigenesis). All but the first ones (T01-T09) would fit into a classical definition of teratogens. The paternal effects were included in line with the recommendation by Schardein (vide supra), and also to incorporate the newest data on this long neglected subject. 

The adverse reproductive effects are considered as being threshold effects, i.e., effects for which there are expected to be a threshold of substance concentration below which the effects will not be manifested. For the hazard and risk assessment, it is important to identify those dose levels at which adverse reproductive effects are observed, and the dose level at which adverse reproductive effects are not observed, i.e., to derive a NOAEL for reproductive toxicity. Crucial in the derivation of the NOAEL and/or LOAEL, is the definition of adverse effects (Section 4.2.2). In the derivation of the NOAEL and/or LOAEL, a number of factors need to be considered these issues are addressed in detail in Sections 4.2.3 and 4.2.4. An alternative approach to the derivation of the... 

Select appropriate procedures to minimize exposure. Use the "basic prudent practices for handling chemicals," which are discussed in Chapter 5, section 5.C, for all work with chemicals in the laboratory. In addition, determine whether any of the chemicals to be handled in the planned experiment meet the definition of a particularly hazardous substance due to high acute toxicity, carcinogenicity, and/ or reproductive toxicity. If so, consider the total amount of the substance that will be used, the expected frequency of use, the chemical s routes of exposure, and the circumstances of its use in the proposed experiment. As discussed in this chapter, use this information to determine whether it is appropriate to apply the additional procedures for work with highly toxic substances and whether additional consultation with safety professionals is warranted (see Chapter 5, section 5.D). 

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