PURPOSE: Findings of studies investigating associations of leisure time physical activity (LTPA) with gestational diabetes mellitus (GDM) risk have been inconsistent. We investigated associations of LTPA with GDM and whether these associations differ by prepregnancy overweight/obese status or gestational weight gain category.
METHODS: Participants (N = 3209) of the Omega study, a pregnancy cohort study in Washington State (1996-2008), reported LTPA duration (h·wk) and energy expenditure (MET·h·wk) in the year before pregnancy and in early pregnancy. Diagnoses of GDM were abstracted from medical records. Poisson regression models were used to determine relative risks of GDM across tertiles of prepregnancy or early pregnancy LTPA duration and energy expenditure. Stratified analyses and interaction terms were used to assess effect modification by prepregnancy overweight/obese status (BMI ≥25 kg·m) or gestational weight gain category (adequate or excessive).
RESULTS: Each tertile increase in prepregnancy LTPA duration or energy expenditure was associated with 15% (95% CI = 0.72-1.00) and 19% (95% CI = 0.69-0.96) lower risk of GDM, respectively. Each tertile increase in early pregnancy LTPA duration or energy expenditure was associated with 16% (95% CI = 0.72-0.97) and 17% (95% CI = 0.72-0.95) lower risk of GDM, respectively. LTPA during both prepregnancy and early pregnancy was associated with a 46% reduced risk of GDM (95% CI = 0.32-0.89) compared with inactivity during both periods. LTPA-GDM associations were similar by prepregnancy BMI and gestational weight gain.
CONCLUSION: Our results support a role for the promotion of physical activity before and during pregnancy in the prevention of GDM.