This article presents a compilation of descriptive data on how work environments can affect reproductive capacity and outcome. A thorough background in issues relevant to reproductive health provides a basis for understanding the effects of work on pregnancy and the effects of pregnancy on work performance. The physical changes of pregnancy and the sequential events by trimester are discussed in relation to work demands and risks. A review of specific job-related risks is also presented, including various chemicals, infections and environmental agents. A third section focuses on the clinical application of taking occupational and reproductive histories, and on guidelines for preconception and pregnancy counseling.