Combined healthy lifestyle in early pregnancy and risk of gestational diabetes mellitus: A prospective cohort study

Abstract Objective To examine the association of a combined healthy lifestyle in early pregnancy with gestational diabetes mellitus (GDM) risk. Design, setting and population A Chinese prospective cohort study with 6980 pregnant women. Methods Individual modifiable lifestyle factors were assessed in early pregnancy and a combined lifestyle score was derived from the sum of the lifestyle factors, with a higher score indicating a healthier lifestyle. The association of a combined healthy lifestyle with GDM risk was examined. Main outcome measures Gestational diabetes mellitus was diagnosed in middle pregnancy according to the International Association of Diabetes and Pregnancy Study Group criteria or diagnoses in medical records. Results Overall, 501 (7.2%) pregnant women were diagnosed with GDM. Being physically active (total energy expenditure in upper three quintiles, i.e. ≥100.1 metabolic equivalent of task [MET]‐hours/week; odds ratio [OR] 0.76, 95% confidence interval [CI] 0.63–0.92), healthy diet (total intake of vegetables and fruits ≥5 times/day; OR 0.74, 95% CI 0.59–0.94), sufficient sleep (night‐time sleep duration ≥7 hours/night; OR 0.66, 95% CI 0.48–0.90) and healthy weight (early‐pregnancy BMI <24.0 kg/m 2 ; OR 0.57, 95% CI 0.46–0.71) were associated with lower GDM risk. The GDM risk decreased linearly across the combined lifestyle score ( P trend <0.001): women with 2, 3 and 4 lifestyle factors compared with those with 0–1 factor had 38% (OR 0.62, 95% CI 0.46–0.84), 57% (OR 0.43, 95% CI 0.31–0.58) and 66% (OR 0.34, 95% CI 0.22–0.52) lower risks of GDM, respectively. Conclusion A healthy lifestyle in early pregnancy was associated with a substantially lower GDM risk.