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Implications of the introduction of new criteria for the diagnosis of gestational diabetes: a health outcome and cost of care analysis
  1. Thomas J Cade1,2,3,
  2. Alexander Polyakov3,4,
  3. Shaun P Brennecke2,3
  1. 1 Diabetes Service, Royal Women’s Hospital, Parkville, Victoria, Australia
  2. 2 Pregnancy Research Service, Department of Maternal Fetal Medicine, Royal Women’s Hospital, Parkville, Victoria, Australia
  3. 3 Department of Obstetrics and Gynaecology, University of Melbourne, Parkville, Victoria, Australia
  4. 4 Department of Reproductive Biology, Royal Women’s Hospital, Parkville, Victoria, Australia
  1. Correspondence to Dr Thomas J Cade; tom.cade{at}


Objective To identify effects on health outcomes from implementing new criteria diagnosing gestational diabetes mellitus(GDM) and to analyse costs-of-care associated with this change.

Design Quasi-experimental study comparing data from the calendar year before (2014) and after (2016) the change.

Setting Single, tertiary-level, university-affiliated, maternity hospital.

Participants All women giving birth in the hospital, excluding those with pre-existing diabetes or multiple pregnancy.

Main outcome measures Primary outcomes were caesarean section, birth weight >90th percentile for gestation, hypertensive disorder of pregnancy and preterm birth less than 37 weeks. A number of secondary outcomes reported to be associated with GDM were also analysed.

Care packages were derived for those without GDM, diet-controlled GDM and GDM requiring insulin. The institutional Business Reporting Unit data for average occasions of service, pharmacy schedule for the costs of consumables and medications, and Medicare Benefits Schedule ultrasound services were used for costing each package. All costs were estimated in figures from the end of 2016 negating the need to adjust for Consumer Price Index increases.

Results There was an increase in annual incidence of GDM of 74% without overall improvements in primary health outcomes. This incurred a net cost increase of AUD$560 093. Babies of women with GDM had lower rates of neonatal hypoglycaemia and special care nursery admissions after the change, suggesting a milder spectrum of disease.

Conclusion New criteria for the diagnosis of GDM have increased the incidence of GDM and the overall cost of GDM care. Without obvious changes in short-term outcomes, validation over other systems of diagnosis may require longer term studies in cohorts using universal screening and treatment under these criteria.

  • obstetrics
  • maternal medicine
  • fetal medicine

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  • Patient consent for publication Not required.

  • Contributors The corresponding author (TC) was responsible for the study design, literature review, collection and analysis of data, interpretation of clinical findings, writing of the manuscript and decision for submission. TC is responsible for the overall content and acts as guarantor. SPB supervised the project and contributed to all of the above in a consulting role. AP contributed to planning and executing appropriate statistical analysis and with interpretation of the data. All authors contributed to the final manuscript review and final submission.

  • Funding The Royal Australian and New Zealand College of Obstetrics and Gynaecology, who awarded the Luke Proposch Perinatal Research Scholarship to the corresponding author to financially support this research. The corresponding author had full access to the data in the study and final responsibility for the decision to submit for publication.

  • Disclaimer This had no role in the study design, data collection, analysis and interpretation, writing of the report or decision to submit for publication.

  • Competing interests None declared.

  • Ethics approval The study was approved as an anonymised audit by the Institutional Research and Ethics Committee with identifying information removed before analysis.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement There are no unpublished data from the study.