A population-based observational study of diabetes during pregnancy in Victoria, Australia, 1999–2008

Objectives This paper reports secular trends in diabetes in pregnancy in Victoria, Australia and examines the effect of including or excluding women with pre-existing diabetes on gestational diabetes (GDM) prevalence estimates. Design Population-based observational study. Setting All births in Victoria, Australia between 1999 and 2008 Participants 634 932 pregnancies resulting in a birth registered with the Victorian Perinatal Data Collection Outcome measures Crude and age-standardised secular trends in pre-existing diabetes and GDM prevalence; secular GDM trends by maternal birthplace; effects on GDM prevalence of including and excluding pre-existing diabetes from the denominator. Results Of the 634 932 pregnancies, 2954 (0.5%) occurred in women with pre-existing diabetes and 29 147 (4.6%) were complicated by GDM. Mean maternal age increased from 29.7 years in 1999 to 30.8 years in 2008. GDM prevalence increased in most maternal age groups. In 2008, age-standardised GDM prevalence was 31% higher than in 1999; secular increases were greater for Australian-born non-Indigenous (29% increase) than immigrant women (12.3% increase). The annual number of pregnancies in women with pre-existing diabetes almost doubled from 1999 to 2008 and prevalence increased from 0.4% to 0.6%. However, including or excluding pre-existing diabetes had little effect on GDM prevalence estimates. Conclusions Pre-existing diabetes and GDM prevalence increased in Victoria between 1999 and 2008 and rising maternal age does not fully explain these trends. These findings have important implications for preventive initiatives. Including or excluding small numbers of women with pre-existing diabetes resulted in minimal changes in GDM estimates. As pre-existing diabetes in young women increases, this methodological issue will likely become important.

[1]  D. Feig,et al.  Trends in Incidence of Diabetes in Pregnancy and Serious Perinatal Outcomes: A Large, Population-Based Study in Ontario, Canada, 1996–2010 , 2014, Diabetes Care.

[2]  J. King,et al.  Methodological Processes in Validating and Analysing the Quality of Population-Based Data: A Case Study Using the Victorian Perinatal Data Collection , 2013, Health information management : journal of the Health Information Management Association of Australia.

[3]  H. McIntyre,et al.  Diagnosing Gestational Diabetes Mellitus: Rationed or Rationally Related to Risk? , 2013, Diabetes Care.

[4]  A. Sinha,et al.  A threefold increase in gestational diabetes over two years: Review of screening practices and pregnancy outcomes in Indigenous women of Cape York, Australia , 2013, The Australian & New Zealand journal of obstetrics & gynaecology.

[5]  M. Biro,et al.  Maternal age, ethnicity and gestational diabetes mellitus. , 2012, Midwifery.

[6]  W. Hoy.  Risk factor trends: age patterns in key health risks over time , 2012 .

[7]  A. Jaradat,et al.  Incidence of gestational diabetes mellitus in Bahrain from 2002 to 2010 , 2012, International journal of gynaecology and obstetrics: the official organ of the International Federation of Gynaecology and Obstetrics.

[8]  G. Hu,et al.  Increasing incidence of gestational diabetes mellitus in Louisiana, 1997-2009. , 2012, Journal of women's health.

[9]  V. Flenady,et al.  Overweight and obesity in Australian mothers: epidemic or endemic? , 2012, The Medical journal of Australia.

[10]  B. Depczynski,et al.  The impact of potential new diagnostic criteria on the prevalence of gestational diabetes mellitus in Australia , 2011, The Medical journal of Australia.

[11]  J. Tuomilehto,et al.  Increasing prevalence of gestational diabetes mellitus in Chinese women from 1999 to 2008 , 2011, Diabetic medicine : a journal of the British Diabetic Association.

[12]  H. Teede,et al.  Risk factors for gestational diabetes mellitus: Implications for the application of screening guidelines , 2011, The Australian & New Zealand journal of obstetrics & gynaecology.

[13]  Roy Taylor,et al.  Gestational diabetes: emerging concepts in pathophysiology , 2010, Obstetric medicine.

[14]  A. Dyer,et al.  International Association of Diabetes and Pregnancy Study Groups Recommendations on the Diagnosis and Classification of Hyperglycemia in Pregnancy , 2010, Diabetes Care.

[15]  A. Sinha,et al.  Maternal and neonatal outcomes in the Torres Strait Islands with a sixfold increase in type 2 diabetes in pregnancy over six years , 2010, The Australian & New Zealand journal of obstetrics & gynaecology.

[16]  Bengt Persson,et al.  International Association of Diabetes and Pregnancy Study Groups Recommendations on the Diagnosis and Classification of Hyperglycemia in Pregnancy , 2010, Diabetes Care.

[17]  W. Callaghan,et al.  Diabetes Trends Among Delivery Hospitalizations in the U.S., 1994–2004 , 2010, Diabetes Care.

[18]  I. Pieris-Caldwell,et al.  Gestational diabetes mellitus in Australia, 2005-06 , 2008 .

[19]  H. P. van der Ploeg,et al.  Sociodemographic Correlates of the Increasing Trend in Prevalence of Gestational Diabetes Mellitus in a Large Population of Women Between 1995 and 2005 , 2008, Diabetes Care.

[20]  M. Cheang,et al.  Gestational diabetes in Manitoba during a twenty-year period. , 2008, Clinical and investigative medicine. Medecine clinique et experimentale.

[21]  C. Roberts,et al.  Outcomes of pregnancies in women with pre‐gestational diabetes mellitus and gestational diabetes mellitus; a population‐based study in New South Wales, Australia, 1998–2002 , 2008, Diabetic medicine : a journal of the British Diabetic Association.

[22]  C. Ananth,et al.  Gestational diabetes in the United States: temporal trends 1989 through 2004. , 2008, American journal of obstetrics and gynecology.

[23]  J. Critchley,et al.  Trends in prevalence and outcomes of pregnancy in women with pre‐existing type I and type II diabetes , 2008, BJOG : an international journal of obstetrics and gynaecology.

[24]  A. Ferrara.  Increasing Prevalence of Gestational Diabetes Mellitus , 2007, Diabetes Care.

[25]  David Korn,et al.  A public health perspective , 2005 .

[26]  N. Cheung,et al.  The Australasian Diabetes in Pregnancy Society consensus guidelines for the management of type 1 and type 2 diabetes in relation to pregnancy , 2005, The Medical journal of Australia.

[27]  T. Frieden,et al.  Trends and racial/ethnic disparities in gestational diabetes among pregnant women in New York City, 1990-2001. , 2005, American journal of public health.

[28]  R. Moses,et al.  Pregestational diabetes and pregnancy: an Australian experience. , 2005, Diabetes care.

[29]  A. Ferrara,et al.  An Increase in the Incidence of Gestational Diabetes Mellitus: Northern California, 1991–2000 , 2004, Obstetrics and gynecology.

[30]  Richard X Davey,et al.  Gestational diabetes in Victoria in 1996: incidence, risk factors and outcomes , 2003, The Medical journal of Australia.

[31]  D. Rouse,et al.  The effect of the increasing prevalence of maternal obesity on perinatal morbidity. , 2001, American journal of obstetrics and gynecology.

[32]  C. Crowther,et al.  Guideline use for gestational diabetes mellitus and current screening, diagnostic and management practices in Australian hospitals , 2001, The Australian & New Zealand journal of obstetrics & gynaecology.

[33]  M. Humphrey,et al.  Decrease in Incidence of Gestational Diabetes Mellitus in Far North Queensland Between 1992 and 1996 , 1999, The Australian & New Zealand journal of obstetrics & gynaecology.

[34]  J. Oats,et al.  Gestational diabetes mellitus ‐ management guidelines: The Australasian Diabetes in Pregnancy Society , 1998, The Medical journal of Australia.

[35]  R. Moses,et al.  The Incidence of Gestational Diabetes Mellitus in the Illawarra Area of New South Wales , 1994, The Australian & New Zealand journal of obstetrics & gynaecology.

[36]  N. Beischer,et al.  Gestational Diabetes and Follow‐up Among Immigrant Vietnam‐born Women , 1993, The Australian & New Zealand journal of obstetrics & gynaecology.

[37]  J. Oats,et al.  Incidence and Severity of Gestational Diabetes Mellitus According to Country of Birth in Women Living in Australia , 1991, Diabetes.

[38]  McHaffie He.  An Australian experience. , 1990 .

[39]  R. Moses,et al.  ADIPS Consensus Guidelines for the Testing and Diagnosis of Gestational Diabetes Mellitus in Australia , 2014 .

[40]  P. Petocz,et al.  Gestational diabetes among Aboriginal Australians: prevalence, time trend, and comparisons with non-Aboriginal Australians. , 2003, Ethnicity & disease.