Physical activity and prevention and treatment of weight gain associated with pregnancy: current evidence and research issues.

PURPOSE The purpose of this study was to examine the evidence in the literature for a relationship between physical activity and weight development during and after pregnancy. METHODS A retrospective analysis of the literature, mainly based on an extended MEDLINE search and the Pregnancy and Childbirth Database (Cochrane), was conducted. RESULTS Weight development during pregnancy is the result of numerous interacting factors, with physical activity being one important determinant of weight outcome and eventually also overweight and obesity. Several methodological matters complicate the interpretation of the interrelationships: generally body weight and not fat has been measured, sociobehavioral confounders have rarely been accounted for, and the time frame to determine the effect of pregnancy on later weight development has been highly variable. Most studies concentrate on the role of physical activity, such as recreational activity and sports, on the safety of the pregnant mother and the fetus. The few studies that address the question of exercise and fat deposition found slightly a smaller increase in skinfold measures in pregnant women who exercised. Factors such as the self-selection of well-educated women under study and of normal body weight, as well as the lack of controls, limit the possibilities to which these results can be extrapolated. CONCLUSION Little information is available on these issues and the quality of information is at most at the evidence type D level, according to the NHLBI classification system. Future research priorities include proper prospective control trials of this important aspect of an obesity preventing life style tool, as well as studies concerning the preventive effects of physical activity on weight retention after pregnancy, an issue not as yet addressed in the literature.