Drug studies in women of childbearing age: ethical and methodological considerations.

Despite a recognized need for the inclusion of women of childbearing age in drug studies, many such studies include only men. This practice is due mainly to the added risk of teratogenicity and to cyclic variations in the menstrual phase and hormonal state. The methodological and ethical problems associated with drug studies in women are demonstrated by a discussion of a proposed study using lithium, a widely used drug that has been shown to have a teratogenic effect in animals and in women with bipolar affective disorder when taken chronically. Practical considerations and solutions for drug studies in women in general are suggested.