Development of a fasting blood glucose-based strategy to diagnose women with gestational diabetes mellitus at increased risk of adverse outcomes in a COVID-19 environment.

OBJECTIVE: To evaluate the role of fasting blood glucose (FBG) to minimise the use of the oral glucose tolerance test in pregnancy (POGTT) for the diagnosis of gestational diabetes mellitus (GDM). RESEARCH DESIGN AND METHODS: We analysed the POGTTs of 26,242 pregnant women in Queensland, Australia, performed between 1 January 2015 and 30 June 2015. A receiver operator characteristics (ROC) assessment was undertaken to indicate the FBG level that most effectively identified women at low risk of an abnormal result. RESULTS: There were 3,946 (15.0%) patients having GDM with 2,262 (8.6%) having FBG ≥ 5.1mmol/l. The ROC identified FBG levels >4.6mmol/l having the best specificity (77%) and sensitivity (54%) for elevated 1 and/or 2hr BGLs. There were 19,321 (73.7%) women having FBG < 4.7mmol/l with a prevalence of GDM of 4.0%, less than 1/3rd the overall rate. Only 4,638 (17.7%) women having FBGs from 4.7-5.0mmol/l would require further evaluation to confirm or exclude the diagnosis. CONCLUSION: This contemporary study of women across the state of Queensland, Australia suggests the FBG can be used effectively to define glucose tolerance in pregnancy, minimising their contact with pathology laboratories and potential exposure to the corona virus. This analysis, used in conjunction with outcome data from the HAPO study, provides reassurance to women and their health professionals that FBG < 4.7mmol/l has both a low rate of abnormal glucose tolerance and minimal adverse pregnancy-associated complications.

Options for screening for gestational diabetes mellitus during the SARS-CoV-2 pandemic.

The balance between avoiding severe acute respiratory syndrome coronavirus-2 contagion and reducing wider clinical risk is unclear for gestational diabetes mellitus (GDM) testing. Recent recommendations promote diagnostic approaches that limit collection but increase undiagnosed GDM, which potentially increases adverse pregnancy outcome risks. The most sensitive approach to detecting GDM at 24-28 weeks beyond the two-hour oral glucose tolerance test (OGTT) is a one-hour OGTT (88% sensitivity). Less sensitive approaches use fasting glucose alone (≥5.1 mmol/L: misses 44-54% GDM) or asking ~20% of women for a second visit (fasting glucose 4.7-5.0 mmol/L (62-72% sensitive)). Choices should emphasise local and patient decision-making.

Testing for gestational diabetes during the COVID-19 pandemic. An evaluation of proposed protocols for the United Kingdom, Canada and Australia.

AIMS: We assessed how altered diagnostic processes and criteria for gestational diabetes mellitus (GDM) recommended by the United Kingdom (UK), Canada and Australia for use during the COVID-19 pandemic would affect both GDM frequency and related adverse outcomes. METHODS: Secondary analysis of 5974 HAPO study women with singleton pregnancies who underwent 75 g OGTTs and HbA1c assays between 24 and 32 weeks' gestation and who received no treatment for GDM. RESULTS: All post COVID-19 modified pathways reduced GDM frequency - UK (81%), Canada (82%) and Australia (25%). Canadian women whose GDM would remain undetected post COVID-19 (missed GDMs) displayed similar rates of pregnancy complications to those with post COVID-19 GDM. Using UK modifications, the missed GDM group were at slightly lower risk whilst the women missed using the Australian modifications were at substantially lower risk. CONCLUSIONS: The modifications in GDM diagnosis proposed for the UK, Canada and Australia result in differing reductions of GDM frequency. Each has both potential benefits in terms of reduction in potential exposure to COVID-19 and costs in terms of missed opportunities to influence pregnancy and postpartum outcomes. These factors should be considered when deciding which protocol is most appropriate for a particular context.