Influence of GDM Diagnosis and Treatment on Weight Gain, Dietary Intake and Physical Activity in Pregnant Women with Obesity: Secondary Analysis of the UPBEAT Study

Obesity during pregnancy is associated with the development of gestational diabetes (GDM). This study aimed to assess if the result of an oral glucose tolerance test (OGTT) for GDM influences health (diet and physical activity) behaviours of pregnant women with obesity. In total, 1031 women who participated in the UK Pregnancies Better Eating and Activity Trial (UPBEAT) of a lifestyle intervention from early pregnancy were included. Changes in weight gain, dietary intake and physical activity following an OGTT undertaken between 27(+0) and 28(+6) weeks’ and 34 and 36 weeks’ gestation were examined using linear regression with appropriate adjustment for confounders. Obese women without GDM (IADPSG criteria) gained 1.9 kg (95% CI −2.2, −1.5, p < 0.001) more weight than women with GDM. Women with GDM demonstrated greater reductions in energy (–142kcal, 95%CI −242.2, −41.9, p = 0.006), carbohydrate intake (−1.5%E 95%CI –2.8, −0.3, p = 0.016) and glycaemic load (–15.2, 95%CI −23.6, –6.7, p < 0.001) and a greater increase in protein intake (2%E, 95%CI 1.3, 2.7, p < 0.001), compared to women without GDM. Trial intervention allocation did not influence any associations observed. The findings emphasise the need for strategies to optimise the health behaviours of pregnant women with obesity, following a negative OGTT for GDM.