In addition to well documented associations with adverse pregnancy outcomes, gestational diabetes (GDM) is a well-recognized risk factor for future (principally Type 2) diabetes, other forms of impaired glucose metabolism (including recurrent GDM in subsequent pregnancies) and future metabolic and cardiovascular risk for both the mother and her child.
Current ADIPS guidelines recommend an initial OGTT at 6 – 12 weeks postpartum, with subsequent follow up determined by future pregnancy plans (women planning another pregnancy are recommended to have a yearly OGTT) and perceived risk of progression to Type 2 diabetes. HbA1c (depending on policies for general diabetes diagnosis) and fasting glucose are noted as possible follow up tests, with details intentionally non-specific.
The National Gestational Diabetes Register gives us the opportunity to vastly improve longitudinal follow up of women with a history of GDM and state based programmes such as “You2” in Queensland also offer valuable support and resources.
All strategies in this area represent a balance between sensitivity (the desire for early detection of diabetes and pre diabetic states) and pragmatism (the desire to have a testing programme that will actually be implemented, rather than simply promoted as the “gold standard”). Recent publications outline the potential role of a combined HbA1c + Fasting glucose strategy to improve sensitivity whilst maintaining pragmatism in “real world” practice.
Even more difficult questions surround intervention strategies for diabetes prevention post GDM. Lifestyle interventions remain attractive in theory, but difficult to implement in practice. The efficacy of thiazolidinediones is supported by randomized trial data, but their unfavourable overall adverse effects make them an unlikely panacea. Metformin has some supportive data, but largely in older women with previous GDM. Bariatric surgery offers potential benefits, but clearly is an invasive option.