Eighty non-exercising pregnant women were assigned randomly to either an exercise group (n = 40) or a control group (n = 40) who did no exercise during pregnancy. At intervals, their perception of health status and well-being was recorded. Of the exercising women, 55% rated their health status as "very good" compared to only 27% of non-exercising women. The women in teh exercise group also gained less weight than those of the control group. The authors conclude that a moderate physical activity program performed over the first, second, and third trimester of pregnancy improves the maternal perception of health status.