Effect of Physical Activity on Postpartum Weight Retention: Findings from the Oregon Pregnancy Risk Assessment Monitoring System (PRAMS)

Rationale: Women who retain pregnancy weight gain are at increased risk of diabetes and other health problems. Methods: The Oregon Pregnancy Risk Assessment Monitoring System (PRAMS) is a stratified, population-based survey of women who have recently given birth. The PRAMS respondents receive a follow-back survey (PRAMS-2) shortly after their child's second birthday. Physical activity was defined as engaging in at least 30 minutes of physical activity at least once a week. Significant weight retention was defined as retaining more than 5kg, calculated by subtracting the pre-pregnancy weight reported in PRAMS from the weight reported in PRAMS-2. Multivariate logistic regression in Stata was used for the analysis. Results: 79.4% of respondents reported partaking in 30 minutes of physical activity at least once a week in the month prior responding to the PRAMS-2 survey. 32.3% of women retained more than 5 kg (~11 lbs) from a previous pregnancy. Overall, women who engaged in at least one day of physical exercise per week were less likely to retain pregnancy weight (adjusted odds ratio: 1.73; 95% confidence interval: 1.04-2.86), after controlling for parity. Conclusions: Engaging in at least 30 minutes of physical activity at least once a week is significantly/non-significantly associated with less retention of pregnancy weight gain. The next step is intervention studies in which women with various levels of pregnancy weight gain are offered support for physical activity to ascertain whether those exercise are more likely to lose their pregnancy weight gain over a period of years.