An assessment of the reliability of 52 enhanced preliminary embryofetal development studies to detect developmental toxicity.

pEFD studies are effective for the detection of serious or irreversible effects on embryofetal development, provided that full fetal examinations are completed. They are not, however, sufficiently powered to reliably define the NOAEL for developmental toxicity. The regulatory impact of pEFD studies remains obscure since maximum pregnancy prevention precautions are required in clinical trials in all regions until the results of the main EFD studies are available.