Figure 1.

Factors varying between preclinical models of POE may differentially influence offspring outcomes. Among other factors, preclinical models of POE frequently differ between the choice of preclinical model employed, the specific type of opioid administered, the method of opioid administration, the length of prenatal exposure, and whether offspring are cross-fostered to unmanipulated, treatment naive dams at birth or remain with the biological mother. Each of these factors may differentially alter offspring outcomes which may make comparing results across studies quite difficult. See text for further details on the advantages and disadvantages of specific preclinical POE models.