Gestational Diabetes Causes

Rebecca McPhee
Dietitian Member of the DAA

3 Minutes

Was it the packet of Tim Tams I ate last week or swapping my morning walk for a sleep-in that did it?  Many women who are diagnosed with gestational diabetes ask themselves what they did to cause their diagnosis.  

The fact is, there is no single cause, and genetic factors like age, ethnic background and family history can all increase your risk.  Interestingly, one in every seven Australian women will be diagnosed with gestational diabetes during pregnancy, and in Canberra, the rates are even higher.

Women planning a pregnancy, in the early stages of pregnancy and between pregnancies can reduce their risk of being diagnosed with gestational diabetes by eating a healthy balanced diet and exercising regularly.


What is gestational diabetes?  

Gestational diabetes occurs during pregnancy when the hormones produced by the placenta block the action of a women's insulin in regulating blood sugar levels. Irregular blood sugar levels can lead to some complications including early labour, bigger babies and high blood pressure for mums - among others. 

Gestational diabetes usually goes away when the baby is born; however, research shows that you have a 30-69% risk of a gestational diabetes reoccuring in future pregnancies and up to 50% risk of developing type 2 diabetes within 10-20 years.

The good news is that in most cases, gestational diabetes can be managed to ensure a healthy mum and bub.  


What do we know about the causes? 

While there isn't just one cause, it is known that several factors can contribute to a diagnosis of gestational diabetes which comes down to genetics, lifestyle and some medications. 


1. Your age 

 Advanced maternal age has become a growing trend in recent years for women in the western world. Research has shown that women over the age of 40 are at a higher risk of gestational diabetes than younger expectant mothers.


2. Genetic factors  

Based on data collected over many years, it is now understood that our ethnic background has an impact on the risk of being diagnosed with gestational diabetes. Being from an Asian, Indian Subcontinent, Aboriginal, Torres Strait Islander, Pacific Islander, Maori, Middle Eastern or non-white African background increases your risk.  

A family history of type 2 diabetes or a first-degree relative (mother or sister) who has had gestational diabetes also increases your risk. 


3. Lifestyle factors 

Women who are above a healthy weight range and/or gain weight rapidly in the first 20 weeks of pregnancy are at higher risk of developing gestational diabetes.  The great news is that research shows healthy levels of exercise during pregnancy can significantly reduce the incidence of gestational diabetes as can following a healthy, balanced diet.


5. A previous diagnosis 

If you have had gestational diabetes in an earlier pregnancy or elevated blood sugar levels in the past, studies suggest you are 30-69% more likely to be diagnosed in a future pregnancy. 


 6. Medications  

Some types of antipsychotic or steroid medications can increase your risk of gestational diabetes. Be sure to ask your GP or pharmacist if you have any questions regarding the long-term-effects of any medications you are currently taking. 


7. Hormones  

If you have polycystic ovarian syndrome (PCOS), there is an increased risk that you will develop diabetes during pregnancy. PCOS is one of the most common hormonal problems in women during their reproductive years, and in most cases are undiagnosed.  

Being aware of the risk factors that we can't change and focus on the ones that we can is a positive first step towards preventing gestational diabetes. Managing a healthy weight by eating well and moving more will not only set you up for a healthy pregnancy but also your future health.  



  • There isn't one factor alone that causes gestational diabetes.  

  • Age, ethnic background and a family history of Gestational Diabetes can make you more predisposed. 

  • If you have had gestational diabetes in a previous pregnancy, your risk in subsequent pregnancies is increased.   

  • Maintaining a healthy weight range; eating a balanced diet and exercising can help decrease your risk.  


For recipes, tips, hacks, events and so much more, join the Capital Chicks CANberra online community today.  



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  • Ming et al. 2018 The effect of exercise during pregnancy on gestational diabetes mellitus in normal-weight women: a systematic review and meta-analysis. BMC Pregnancy and Childbirth volume 18, Article number: 440 (2018). 
  • Mijatovic-Vukas. J et al. Associations of Diet and Physical Activity with Risk for Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis. Nutrients 2018, 10(6), 698; 
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