Understanding health behaviours in a cohort of pregnant women at risk of gestational diabetes mellitus: an observational study

Objective To assess health behaviours, physical activity levels, weight gain and development of gestational diabetes mellitus (GDM) in high-risk women. Design An observational sub-study of a larger randomised controlled trial. Setting A large tertiary hospital in Australia. Population Ninety-seven women (mean age 31.7 +/- 4.5 years; body mass index 30.3 +/- 5.9 kg/m(2)) at risk of developing GDM. Methods Women were identified as at risk of GDM based on a validated screening tool. Baseline measures were completed at 12-15 weeks of gestation and repeated at 26-28 weeks of gestation. Main outcome measures Anthropometric (weight and height) and physical activity assessment (Yamax pedometer and International physical activity questionnaire), questionnaires (self-efficacy) and GDM screening. Results By 28 weeks of gestation, there was a high GDM prevalence of 26% using the recent International Association of Diabetes and Pregnancy Study Group criteria. Weight gain in overweight (body mass index 25-29.9 kg/m 2) and obese (body mass index > 30.0 kg/m(2)) women exceeded minimum total weight gain recommendations set by the Institute of Medicine (P < 0.01). Physical activity levels were low and declined during pregnancy (5437 +/- 2951 steps/day to 4096 +/- 2438 steps/day, respectively, P < 0.001). Despite reduced activity levels, increased weight gain and high GDM incidence many women did not accurately perceive GDM risk and were confident in their ability to control weight. A significant association with physical activity, weight and GDM outcome was not observed. Conclusions Overweight and obese pregnant women at risk for developing GDM demonstrate excessive weight gain and a reduced level of physical activity observed from early pregnancy to 28 weeks of gestation. Results highlight the need for targeted intervention in women at risk for developing GDM. Australian New Zealand Clinical Trial Registry Number: ACTRN12608000233325.