Gestational diabetes (GD) is a growing problem among Australian women. Around 5% of women aged 15 to 49 years were diagnosed with GD in 2005-6, an increase of over 20% since 2000-01.1
The risk increases with age from 1% among 15 to 19-year olds to 13% among women aged 44 to 49 years and is 1.5 times higher among Aboriginal and Torres Strait Islander women than among other Australian women. Women born overseas are twice as likely to develop GD than women born in Australia, with the incidence being highest among women born in Southern Asia—at least 3.4 times the rate of women born in Australia.1
Other risk factors include:1
▪ Detectable levels of glucose in urine
▪ Age >30 years
▪ BMI >25 at time of conception
▪ Poor pregnancy outcomes in the past
▪ Family history of Type 2 diabetes mellitus (T2DM) or GD or glucose intolerance
Screening and diagnosis
Universal screening for gestational diabetes has been recommended in Australia since 1998.2 All women not known to have GD should have a 75g oral glucose tolerance test (OGTT) at 24 -28 weeks gestation. GD is diagnosed if one or more of the following criteria are met:
▪ Fasting glucose ≥5.1 mmol/L
▪ 1-hr glucose ≥10.0 mmol/L
▪ 2-hr glucose ≥8.5 mmol/L
Once a diagnosis has been made, women need to be informed about the implications of GD and educated on how to perform home blood glucose monitoring. Finger-prick testing should be performed four times a day, ideally before breakfast and 2 hours after each meal.3
The following self monitoring blood glucose treatment targets are suggested:2
▪ Fasting capillary blood glucose (BG): ≤5.0 mmol/L
▪ 1-hour BG after commencing meal: ≤7.4 mmol/L
▪ 2 hour BG after commencing meal: ≤6.7 mmol/L
In most cases, dietary intervention should be the first step. Moderate intensity exercise can decrease insulin resistance and should be encouraged. Insulin is the cornerstone of pharmacotherapy and is used in around 30% to 40% of cases. Insulin should be considered when blood glucose concentrations exceed recommended targets two or more times in one week. GPs should consider metformin for women who either refuse or are unable to take insulin.3
Women diagnosed with GD have a 30% risk of a recurrence in GD in subsequent pregnancies and up to 50% risk of developing Type 2 diabetes mellitus within 10-20 years. Women contemplating another pregnancy should have an (OGTT) annually. Women who are being tested for possible Type 2 DM should have an OGTT or an HbA1c. Where there is lower risk, a fasting plasma glucose test should be sufficient.
Resources are available for Download from the National Diabetes Services Scheme (NDSS) Languages available: English, Arabic, Turkish, Vietnamese, Traditional Chinese and Simplified Chinese.
[Please note: We could add images to this post at a later date]
For more information on Gestational Diabetes go to:
Diabetes Australia www.diabetesaustralia.com.au/en/Living-with-Diabetes/Gestational-Diabetes/
Download the ADPIS Consensus Guidelines
Read The Conversation: Diabetes among Aboriginal Australians at crisis point
- AIHW: Templeton M & Pieris-Caldwell I 2008. Gestational diabetes mellitus in Australia, 2005–06. Diabetes series no. 10. Cat. no. CVD 44. Canberra: AIHW.
- Donovan P, McIntyre, HD. Drugs for gestational diabetes. Aust Prescr 2010;33:141-4.
3. Nankervis A, McIntyre HD, Moses R, Ross GP, Callaway L, Porter C, Jeffries W, Boorman C, De Vries B. ADIPS Consensus Guidelines for the Testing and Diagnosis of Gestational Diabetes Mellitus in Australia. Australasian Diabetes in Pregnancy Society.