Prevention of Gestational Diabetes in Pregnant Women with Obesity: Protocol for a Pilot Randomised Controlled Trial

BackgroundObesity in pregnancy increases the risk of gestational diabetes mellitus (GDM) and associated adverse outcomes. Despite metabolic differences, all pregnant women with obesity are considered to have the same risk of developing GDM. Improved risk stratification is required to enable targeted intervention in women with obesity who would benefit the most. The aim of this study is to identify pregnant women with obesity at higher risk of developing GDM and in a pilot randomised controlled trial (RCT), show efficacy of a lifestyle intervention and/or metformin to improve glycaemic control.MethodsWomen aged 18 years or older with a singleton pregnancy and body mass index (BMI) ≥30kg/m2 will be recruited from one maternity unit in London, UK. Risk of GDM will be assessed using a multivariable GDM prediction model combining maternal age, mid-arm circumference, systolic blood pressure, serum triglycerides and whole blood HbA1c. Women identified at higher risk of developing GDM will be randomly allocated to one of two intervention groups (lifestyle advice with or without metformin) or standard antenatal care. Primary outcome; reduction in mean glucose/24hr of 0.5mmol/l as assessed by continuous glucose monitoring. A sample of 60 high risk women is required.DiscussionEarly risk stratification of GDM in pregnant women with obesity and targeted intervention using lifestyle advice with or without metformin could improve glucose tolerance compared to standard antenatal care. If successful, an adequately powered RCT will be performed to investigate whether this strategy is effective in preventing GDM in women with obesity. Ethics and trial registrationThis study has been approved by the NHS Research Ethics Committee (UK IRAS integrated research application system; reference 18/LO/1500). EudraCT Number 2018-000003-16.