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 liter ature for a relationship between physical activity and weight development d uring and after pregnancy. Methods: A retrospective analysis of the literat ure, mainly based on an extended MEDLINE search and the Pregnancy and Child birth Database (Cochrane), was conducted. Results: Weight development durin g pregnancy is the result of numerous interacting factors, with physical ac tivity being one important determinant of weight outcome and eventually als o overweight and obesity. Several methodological matters complicate the int erpretation of the interrelationships: generally body weight and not fat ha s been measured, sociobehavioral confounders have rarely been accounted for , and the time frame to determine the effect of pregnancy on later weight d evelopment has been highly variable, Most studies concentrate on the role o f physical activity, such as recreational activity and sports, an the safet y of the pregnant mother and the fetus. The few studies that address the qu estion 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 resul ts can be extrapolated. Conclusion: Little information is available on thes e issues and the quality of information is at mast at the evidence type D l ever, according to the NHLBI classification system. Future research priorit ies include proper prospective control trials of this important aspect of a n obesity preventing life style tool, as well as studies concerning the pre ventive effects of physical activity on weight retention after pregnancy, a n issue not as yet addressed in the literature.