Gestational diabetes is quite closely linked with type 2 diabetes

Explore causes

The causes of gestational diabetes are partly known but there is still a significant amount that is not yet understood.

The root cause of gestational diabetes is resistance to insulin and therefore it shares some of the causes of type 2 diabetes.


Hormones play a large part in pregnancy and the increased levels of certain hormones can lead to a greater risk of health problems developing.

In the case of gestational diabetes, each of the following hormones can decrease the body’s ability to properly respond to insulin:

  • Oestrogen
  • Progesterone
  • Human placental lactogen (HPL)

The further into pregnancy you are, the more of these hormones will be produced which explains why gestational diabetes tends to develop during the latter half of pregnancy – usually after 28 weeks (third trimester).

The mechanisms of exactly how these hormones cause diabetes is yet to be fully understood.

Link with causes of type 2 diabetes

Gestational diabetes is closely linked with type 2 diabetes and indeed many mothers that have experienced gestational diabetes during pregnancy go on to develop type 2 diabetes later in life.

The following factors are known to increase the chance of gestational diabetes developing:

  • Having a high BMI leading up to pregnancy – a BMI of 30 or more
  • Having a family history of either gestational diabetes or type 2 diabetes

Other risk factors for gestational diabetes

The following factors are also associated with an increased risk of getting gestational diabetes:

  • Having had gestational diabetes in a previous birth
  • Having given birth to a large baby – 9 lbs (4.1 kg) or more
  • Being of African Caribbean, Hispanic, American Indian or Asian descent