Testing and diagnosis

The 2014 Australasian Diabetes in Pregnancy Society (ADIPS) consensus guidelines (Nankervis et al. 2014) recommend early testing in pregnancy for women with risk factors for gestational diabetes using the 75g pregnancy Oral Glucose Tolerance Test (OGTT). Routine testing for gestational diabetes using the OGTT is recommended for all women at 24–28 weeks gestation, including higher risk women recording normal blood glucose results in early pregnancy.

Diagnostic criteria

A diagnosis for gestational diabetes is made based on the 75g OGTT with one or more of the following values:

  • Fasting plasma glucose ≥5.1mmol/L
  • 1-hour post 75g oral glucose load ≥10.0 mmol/L
  • 2-hour post 75g oral glucose load ≥8.5 mmol/L.

The ADIPS guidelines recommend re-testing with the 75g OGTT at 6–12 weeks post-partum for women diagnosed with gestational diabetes (identifying ongoing glucose abnormalities which may indicate other forms of diabetes, first detected in pregnancy) and regular ongoing monitoring due to the high risk of recurrence in subsequent pregnancy and of developing type 2 diabetes in the future.


Nankervis A, Mclntyre HD, Moses R, Ross G, Callaway L, Porter C et al. 2014. ADIPS consensus guidelines for the testing and diagnosis of gestational diabetes mellitus in Australia. Sydney: Australasian Diabetes in Pregnancy Society.