Overview affects 5-10% of pregnancies. Incidence varies between nutritional and genetic factors. Risk of GDM increases with age. Women born in Southern Asia are at particularly higher risk. 50% change of mother to develop Type II Diabetes later in life.

Clinical Presentation generally asymptomatic

Classic signs of Type II Diabetes (4P's)

• Polyphagia
• Polydipsia
• Parasaethsia
• Polyuria

Screening/Diagnosis

In Australia oral glucose tolerance test (75g) at 24 and 28weeks.

• Test at 1 hour >10 or 2 hour >8.5
• Fasting glucose 5.1 hour

Normal Physiology

• Maternal metabolism switches from carbohydrates to fat utilisation
• Subsequent pancreatic beta cell hyperplasia
• Increased insulin secretion
• Early increase in insulin sensitivity causes progressive insulin resistance.

Pathophysiology

• Placenta produces growth hormone, CRH,  placental lactinogen and progesterone.
• These hormones promote glucose intake by the fetus by causing insulin resistance in the mother
• Hyperglycaemia in circulation eventually cause the release of fetal insulin causing insulinaemia

Management Diagnosis GDM then management of a multidisciplinary team (i.e endocrinologist, diabetic educator).

• Monthly ultrasound to check for foetal macrosomia.
• Diet, exercise and blood glucose monitoring.
• If glucose unstable change to insulin.
• Induction of labour if continuously unstable gestational diabetes before term or early at term - to prevent complications
• Postpartum (after delivery) stop insulin and glucose infusions, check blood glucose prior to discharge, follow up 6 weeks for oral glucose tolerance test, educate (as 50% risk of developing diabetes mellitus over the next 25years).