A systematic literature review was conducted to investigate the effects of physical activity during pregnancy on selected maternal-child health outcomes. The search included articles published from 1980 to 2005 in the MEDLINE and LILACS databases using key words such as physical activity, physical exercise, pregnancy, and gestation. The methodological quality of 37 selected articles was evaluated. It appears to be a consensus that some light-to-moderate physical activity is not a risk factor and may even be considered a protective factor for some outcomes. However, some studies found an association between specific activities (e.g., climbing stairs or standing for long periods) and inadequate birth weight, prematurity, and miscarriage. Few studies found an association between physical activity and maternal weight gain, mode of delivery, or fetal development. Further research is needed to fill these gaps and provide guidelines on the intensity, duration, and frequency of physical activity during pregnancy.