Animal models: their use and limitations in long-term safety evaluation of fertility-regulating agents

Animal studies are usually to predict the value of new compounds and to assess their incorporation into schemes to reduce or clarify recognized hazards. There are two assumptions, that animal models are appropriate and dose-response relationship can be derived. Such tests cannot provide definite evidence about the safety of such medical agents in man. Examples are given of data arising from studies of progestogens or oestrogens in animals in relation to clinical conditions. The scientific quality of these tests depends on the adequacy of an appropriate design, competent staff and a correct evaluation of the results.