Gestational diabetes in women with obesity; an analysis of clinical history and simple clinical/anthropometric measures.

Aim: We assessed clinical risk factors, anthropometric measures of adiposity and weight gain to determine associations with development of GDM in a cohort of pregnant women with obesity.

Methods: This was a secondary analysis of the UPBEAT trial of a complex lifestyle intervention in pregnant women with obesity (ISRCTN89971375). Clinical risk factors, and measures of adiposity and weight were assessed in the early 2nd trimester (mean 17 +0 weeks), and adiposity and weight repeated in the early 3rd trimester (mean 27 +5 weeks').

Results: Of the 1117 women (median BMI 35.0 kg/m2) with complete data, 25.8% (n = 304) developed GDM (IADPSG criteria, OGTT 24-28weeks). Using multivariable analysis, early clinical risk factors associated with later development of GDM included age (adj OR 1.06 per year; 95% CI 1.04-1.09), previous GDM (3.27; 1.34-7.93) and systolic blood pressure (per 10mmHg, 1.34; 1.18-1.53). Anthropometric measures positively associated with GDM included second trimester (mean 17+0 weeks) subscapular skinfold thickness, (per 5mm, 1.12; 1.05-1.21), and neck circumference (per cm, 1.11; 1.05-1.18). GDM was not associated with gestational weight gain, or changes in skinfolds thicknesses or circumferences between visits.

Conclusions: In this cohort of women with obesity, we confirmed clinical risk factors for GDM, (age, systolic blood pressure) previously identified in heterogeneous weight women but add to these indices of adiposity which may provide a discriminatory approach to GDM risk assessment in this group. This study also underscores the need to focus on modifiable factors pre-pregnancy as an opportunity for GDM prevention, as targeting gestational weight gain and adiposity during pregnancy is likely to be less effective.