Gestational diabetes

Question 1

What are the risk factors for developing gestational diabetes?

Answer 1

• Previous gestational diabetes
• Previous foetus >4.5kg
• Previous unexplained stillbirth
• 1st degree relative with diabetes
• BMI >30
• Racial origin (usually South Asian, black Caribbean, and Middle Eastern are at increased risk)

Question 2

What foetal complications are associated with gestational diabetes?

Answer 2

• Congenital abnormalities (esp NTD and cardiac defects) are 3-4 times more common
• Preterm labour in >10% of women with established diabetes
• Reduced foetal lung maturity
• Increased birthweight making shoulder dystocia and birth trauma more likely
• Foetal compromise, foetal distress in labour and sudden foetal death are more common

Question 3

What maternal complications are associated with gestational diabetes?

Answer 3

• Ketoacidosis is rare, but hypoglycaemia may result from attempts to achieve optimum glucose control
• UTI and wound or endometrial infection after delivery are more common
• Pre-existing hypertension and pre-eclampsia are more common
• Makes pre-existing ischaemic heart disease worse
• C-section or instrumental delivery is more likely
• Impaired kidney function in 5-10% of women which is also associated with poorer foetal outcomes
• Eye problems (diabetic retinopathy)

Question 4

What additional pre-conceptual care is required of women who already have diabetes?

Answer 4

Glucose levels:

• Monthly HbA1c
• Level of <6.5% is best and pregnancy not advised if >10%
• Fasting glucose levels should be between 4-7 mmol/L
• Metformin and insulin are fine to use during pregnancy, any other diabetes medications should be changes

Other:

• 5mg folic acid (conception and 1st 12 weeks)
• Stop any statins
• Switch to pregnancy-safe anti-hypertensives if required
• Assess kidney function, BP, and eyes

Question 5

What screening should be done for women with a previous history of gestational diabetes?

Answer 5

• OGTT at/soon after booking visit
• OGTT again at 24-28 weeks if first test normal
• Ideal results:
  (i) fasting glucose <5.6 mmol/L
  (ii) 2-h glucose <7.8 mmol/L

Question 6

What screening should be done for women with no previous history of gestational diabetes, but with some risk factors?

Answer 6

• OGTT at 24-28 weeks
• Ideal results:
  (i) fasting glucose <5.6 mmol/L
  (ii) 2-h glucose <7.8 mmol/L

Question 7

What management is typically offered to women with a fasting glucose <7 mmol/L?

Answer 7

Trial of diet and exercise for 1-2 weeks

Question 8

What management is typically offered to women who have failed trial of diet and exercise but fasting glucose is still <7 mmol/L?

Answer 8

Metformin

Question 9

What management is offered to women who have failed management of diet/exercise and metformin?

Answer 9

Short-acting insulin

long-acting insulin is not used in gestational diabetes

Question 10

What fasting glucose and 2h OGTT results indicate immediate treatment with insulin?

Answer 10

• Fasting glucose ≥5.6 mmol/L

- 2h glucose ≥7.8 mmol/L

Question 11

What are the blood glucose targets for women with gestational diabetes?

Answer 11

• Fasting: ≤5.3 mmol/L
• 1h after meals: ≤7.8 mmol/L
• 2h after meals: ≤6.4 mmol/L