Change to gestational diabetes testing: a pandemic silver lining?

A change to gestational diabetes testing has been incorporated into the Queensland Clinical Guidelines for COVID-19 pandemic screening, following formal evaluation funded by a Royal Brisbane and Women’s Hospital (RBWH) Foundation research grant.

The change involved replacing a full oral glucose tolerance test, requiring pregnant women to sit for 2–3 hours in a pathology laboratory, with a one-off blood test for gestational diabetes mellitus (GDM). About one in seven pregnant Australians are diagnosed with GDM, usually between the 24th and 28th weeks of pregnancy. As a result, more than 300,000 oral glucose tests are performed in Australia each year.

The new testing regime came about as a result of COVID-19, with health authorities seeking to minimise the risk of virus exposure and reduce pressure on the health system.

Associate Professor Susan de Jersey, RBWH Advanced Dietitian Team Leader and Clinician Research Fellow, said that during planning for the pandemic, RBWH researchers were able to mesh local data with urgent healthcare priorities, developing a new algorithm to spearhead GDM screening and diagnosis changes.

They offered women a one-off fasting blood test and only proceeded to traditional oral glucose testing if the results indicated an elevated fasting blood glucose level. It is estimated 4 in 5 women could avoid the lengthier test by applying this algorithm.

The evaluation of the pandemic screening, published in the Medical Journal of Australia, found that the perinatal outcomes of women excluded as having GDM based on a fasting glucose level during the pandemic were similar to outcomes for women who did not have GDM on a full oral glucose tolerance test before the pandemic.

“Identifying women at low absolute risk of gestational diabetes-related pregnancy complications on the basis of FVPG [fasting venous plasma glucose] assessment as an initial step in GDM screening could reduce the burden for pregnant women and save the health system substantial costs,” de Jersey said.

RBWH Foundation CEO Simone Garske said that a reduction in unnecessary glucose testing may well be one of the silver linings of the cloud cast by COVID-19.

“To think RBWH Foundation-funded research may reduce the need for this test for potentially thousands of women each year is extremely exciting,” she said.

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