Gestational Diabetes

Question 1

What are some risk factors for gestational diabetes?

Answer 1

BMI > 30kg/m2
Previous macrosomic baby - 4.5kg or above
Previous history of gestational diabetes
Family history of diabetes (1st degree with T1DM or T2DM)
Ethnic predisposition (Asian, Black Carribean, Middle Eastern)
Long term steroid therapy

Test for diabetes if one or more of the risk factors is present at 28 weeks gestation

Question 2

What are some fetal complications of GDM (growth related)?

Answer 2

Large abdominal circumference
Congenital defects - neural tube
Large for gestational age
Polyhydramnios
Macrosomia

Question 3

What are some fetal complications of GDM (on delivery)

Answer 3

Hypoglycemia
Shoulder dystocia –> brachial plexus injury
Neonatal jaundice
Polycythaemia

Hypomagnesemia
Respiratory Distress Syndrome
Instrumental delivery

Question 4

What is the gold standard for gestational diabetes diagnosis and what are the cutoffs?

Answer 4

2 hour 75g oral glucose tolerance test at 24-28 weeks gestation

• fasting blood glucose level of 5.6mmol/litre or above
• 2-hour plasma glucose level (after glucose administration) of 7.8mmol/litre or above

Question 5

Treatments for GDM

Answer 5

Diet control and exercise (1st line)

Metformin - if blood glucose targets not met using diet changes within 1 - 2 weeks

Insulin (Offer if fasting plasma glucose > 7.0mmol/L with or without metformin, as well as changes in diet and exercise )

Glibenclamide (if patient cannot tolerate metformin/declines insulin)

Question 6

What other test to offer if diagnosed with gestational diabetes?

Answer 6

HbA1c to check for pre-existing T2DM