Gestational diabetes (Complete)

Question 1

Define GDM

Answer 1

Glucose intolerance that begins or is detected in pregnancy

Question 2

What percentage of pregnancy lead to GDM?

Answer 2

5%

Question 3

What is the risk of developing diabetes later on in life in patients with GDM?

Answer 3

50%

Within 5-10 years post-partum

Question 4

What are the main risk factors of GDM?

Answer 4

Ethnicity

Fhx of DM

Previous GDM

Maternal obesity (BMI >30)

Delivery of macrosomic babies (>4 kg)

Previous stillborn pregnancy or perinatal death

Question 5

What are the main clinical features of GDM?

Answer 5

Typically asymptomatic and picked up through screening

Fatigue

Polyuria

Thirst

Question 6

When are women with a previous history of gestational diabetes screened?

Answer 6

Screened as soon as possible from pregnancy booking visit

Followed by another test at 24-28 weeks

Question 6

When are women typically screened for gestational diabetes?

Answer 6

24-28 weeks

Question 7

What differentials should be considered alongside gestational diabetes?

Answer 7

T1DM or T2DM

Question 8

What investigation is used in screening for gestational diabetes?

Answer 8

Oral glucose tolerance test (OGTT)

Question 9

What findings in OGTT confirm a diagnosis of gestational diabetes?

Answer 9

Fasting blood glucose level: ≥5.6 mmol/L

2-hour plasma glucose level: ≥7.8 mmol/L

‘diagnosis of GDM is as easy as 5678’

Question 10

What additional tests may be considered alongside OGTT?

Answer 10

HbA1c: Helpful in distinguishing between GDM and T1/2DM

Urinalysis: Check for glycosuria

Question 11

What investigation can help distinguish between GDM and pre-existing diabetes?

Answer 11

HbA1c

> 48 mmol/L in pre-existing diabetes

Question 12

How are patients with GDM managed?

Answer 12

Depends on fasting blood glucose levels

_ If < 7 mmol/L_:

1) Lifestyle modifications

• Low glucose diet
• Physical activity

2) Metformin

• Offer if blood glucose targets not met within 1-2 weeks of lifestyle modification

If > 7 mmol/L:

1) Insulin +/- metformin

Conservative:

Post-partum follow-up for future T2DM

Question 13

What target glucose levels should be met for patients with GDM?

Answer 13

Fasting: 5.3 mmol/litre

1 hour after meals: 7.8 mmol/litre

2 hours after meals: 6.4 mmol/litre

Question 14

What is first-line management for patients with fasting glucose < 7?

What additional management required if first-line measures fail?

Answer 14

Lifestyle modification (e.g. physical activity, low glycaemic index)

Second-line: Metformin

Question 15

What is first-line management for patients with fasting glucose > 7?

Answer 15

Insulin +/- metformin

Question 16

How should patients with GDM be followed up post-natally?

Answer 16

Long-term community follow-up for risk of T2DM

Question 17

What foetal complications occur due to GDM?

Answer 17

Growth and delivery-related complications:

• Macrosomia (> 4kg) [Shoulder dystocia, birth injuries, emergency C-section]
• Pre-term birth (NRDS)

Metabolic complications:

• Neonatal hypoglycaemia
• Increased risk of T2DM later in life

Congenital anomalies:

• Sacral agenesis

Question 18

Why are neonates born from mothers with GDM susceptible to neonatal hypoglycaemia?

Answer 18

Due to hyperglycaemic environment antanatally, neonate produces high levels of insulin

After birth, these high levels of insulin can hence cause a hypoglycaemia

Question 19

What maternal complications can occur due to GDM?

Answer 19

Increased risk of T2DM

Increased risk of hypertension and pre-eclampsia

Perineal tears (due to macrosomia)

Question 20

How are patients with pre-existing diabetes managed?

Answer 20

Converntional:

Weight loss targets (BMI < 27)

Detailed anomaly scan at 20 weeks

Medication: Strict glycaemic control

Start insulin

Stop oral hypoglycaemic agents except metformin

Folic acid 5 mg/day from pre-conception to 12 weeks gestation

Treat worsening retinopathy (gets worse during pregnancy)