Pre-Pregnancy Fitness and Risk of Gestational Diabetes: A Longitudinal Analysis.

PURPOSE: To assess the associations of pre-pregnancy cardiorespiratory fitness, moderate-to vigorous-intensity physical activity (MVPA), and time spent watching television with subsequent development of gestational diabetes mellitus (GDM).METHODS: Participants were 1,333 women enrolled in the Coronary Artery Risk Development in Young Adults (CARDIA) study who did not have diabetes either at baseline (1985-86) or prior to births occurring after baseline. Baseline fitness was estimated using a graded symptom-limited maximal exercise treadmill test and expressed in metabolic equivalent (MET) units. Baseline MVPA (exercise units/day) was measured using the CARDIA physical activity history questionnaire, and television viewing (hours/day) was assessed by self-report in 1990-91. Logistic regression analysis was used to derive odds ratios (OR) and 95% confidence intervals (CI), adjusting for time from baseline to delivery and baseline study center, age, race, education, parity, family history of diabetes, smoking, alcohol, saturated fat intake, waist circumference, HOMA-IR, and HDL-Cholesterol.RESULTS: Over 25 years of follow up, 164 women developed GDM. The odds of developing GDM were 21% lower for each 1 standard deviation increment in baseline level of fitness (2.3 METs; OR 0.79, 95% CI 0.65, 0.96). Pre-pregnancy MVPA and television viewing were not statistically associated with the development of GDM.CONCLUSION: Study findings indicate that objectively assessed pre-pregnancy fitness, but not self-reported MVPA or television time, is associated with GDM. Clinicians should counsel women on the benefits of improving fitness in the pre-conception period, particularly among women at greater risk for GDM.

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