Note that where there is a Gestational diabetes mellitus (GDM) and a current history of Pre-existing Type 2 diabetes then record Code 2 Pre-existing Type 2 diabetes.

While most women will know what type of diabetes they have, where their type of diabetes is unknown the clinician should leave the collection form/system blank. This will be coded as a '9' by the data custodian.

CODE 1   Pre-existing Type 1 diabetes

Beta-cell destruction, usually leading to absolute insulin deficiency. Includes those cases attributed to an autoimmune process, as well as those with beta-cell destruction and who are prone to ketoacidosis for which neither an aetiology nor pathogenesis is known (idiopathic). It does not include those forms of beta-cell destruction or failure to which specific causes can be assigned (e.g. cystic fibrosis, mitochondrial defects). Some subjects with Type 1 diabetes can be identified at earlier clinical stages than 'diabetes mellitus'.

CODE 2   Pre-existing Type 2 diabetes

Type 2 includes the common major form of diabetes, which results from defect(s) in insulin secretion, almost always with a major contribution from insulin resistance.

CODE 3   Gestational diabetes mellitus (GDM)

GDM is a carbohydrate intolerance resulting in hyperglycaemia of variable severity with onset or first recognition during pregnancy. The definition applies irrespective of whether or not insulin is used for treatment or if the condition persists after pregnancy.

Diagnosis is to be based on the Australasian Diabetes in Pregnancy Society (ADIPS) Guidelines (Nankervis et al. 2014). If the clinician does not have information as to whether these guidelines have been used, available information about diagnosis of GDM is still to be reported.

CODE 8   Other type of diabetes mellitus

This categorisation include less common causes of diabetes mellitus, but are those in which the underlying defect or disease process can be identified in a relatively specific manner. They include, for example, genetic defects of beta-cell function, genetic defects in insulin action, diseases of the exocrine pancreas, endocrinopathies, drug or chemical-induced, infections, uncommon forms of immune-mediated diabetes, other genetic syndromes sometimes associated with diabetes. Impaired glucose regulation is not to be included here.

CODE 9   Not stated/inadequately described

To be recorded by data entry personnel (state/territory health authority) if the data field is left blank or is inadequately completed in the perinatal data collection form or extract. Clinicians should not record Code 9.

Nankervis A, McIntyre HD, Moses R, Ross GP, Callaway L, Porter C et al. 2014. Australasian Diabetes In Pregnancy Society (ADIPS) Consensus Guidelines for the Testing and Diagnosis of Hyperglycaemia in pregnancy in Australia and New Zealand. Sydney: ADIPS. Viewed 18 September 2020,http://www.adips.org/downloads/2014ADIPSGDMGuidelinesV18.11.2014_000.pdf