Weight gain, total fat gain and regional fat gain during pregnancy and the association with gestational diabetes: a population-based cohort study

OBJECTIVE: In a multi-ethnic population-based study, we investigate the change in indicators of adiposity (being weight gain and gain of total fat, truncal fat and mean skinfold thickness) from early pregnancy to 28 weeks of gestation overall and across ethnic groups, and explore the association between the change in indicators of adiposity and gestational diabetes (GDM). DESIGN: Weight, skinfold thickness and bioelectrical impedance analysis were performed twice in 728 pregnant women in gestational week 15 (visit 1) and week 28 (visit 2). GDM was defined by the modified International Association of Diabetes in Pregnancy Study Group (IADPSG) criteria (1-hour glucose not available). RESULTS: An increase in all indicators of adiposity gave increased odds ratios (OR) for GDM. After adjusting for pre-pregnant body mass index, a 0.14 kg per week (one standard deviation (s.d.)) increase in truncal fat gave an OR of 1.31 (95% CI 1.10-1.56), while a 0.21 kg per week (one s.d.) weight gain gave an OR of 1.23 (95% CI 1.04-1.46) for GDM. The ORs for the indicators of adiposity remained after additional adjustments for insulin resistance in early pregnancy. When combining the effects of an ethnic origin, 0.14 kg per week (one s.d.) truncal fat gain and 4.7 kg m(-2) (one s.d.) increased pre-pregnant BMI the OR for South Asians was 5.9 (3.5-10.0) versus 2.1 (1.6-2.8) for Europeans. CONCLUSION: Weight gain and gain of total fat mass, mean skinfold thickness and especially truncal fat were all positively associated with GDM. South Asians, in particular, should be encouraged to avoid an excessive weight gain during pregnancy to reduce risk of GDM.