8.16 Gestational Diabetes

Question 1

What causes GDM?

Answer 1

reduced insulin sensitivity

Question 2

What are the main complications of GDM?

Answer 2

• large for dates and macrosomia
• shoulder dystocia
• women are at risk of T2DM longer term

If mum has diabetes:

• Neonatal HYPOGLYCAEMIA
• Polycythaemia (raised haemoglobin)
• Jaundice (raised bilirubin)
• Congenital heart disease
• Cardiomyopathy
• (macrosomia)

Question 3

Who should be screened / tested for GDM?

Answer 3

• previous GDM
• previous macrosomic baby (≥4.5)
• BMI >30
• FHx diabetes in 1st degree relative
• ethnic origin: black Caribbean, Middle Eastern, South Asian
• polyhydramnios
• large for dates
• glucose 2+ on dipstick or 1+ twice

Question 4

How much glucose and time in an OGTT?

Answer 4

75g glucose, measure fasting and then 2hours.

Question 5

What are normal OGTT results?

Answer 5

fasting: <5.6 mmol/L
2hr: 7.8 mmol/L

(5-6-7-8)

Question 6

How often do GDM women get US scans?

Answer 6

weekly to check fetal growth and amniotic fluid volume between 28 and 36 weeks.

Question 7

What are 3 initial management options for GDM depending on fasting glucose results?

Answer 7

< 7mmol/L = diet and excursion for 1-2weeks, add metformin, add insulin

> 7mmol/L = insulin ± metformin

> 6mmol/L AND macrosomia = insulin ± metformin

Question 8

What drug can be offered if women decline insulin or can’t tolerate metformin?

Answer 8

Glibenclamide (sulfonylurea)

Question 9

GDM women need to monitor glucose several times a day, what are their BM targets?

Answer 9

fasting: 5.3 mmol/L
1hr post meal: 7.8mmol/L
2hr post meal: 6.4mmol/L
avoid 4mmol/L or below

Question 10

What supplement should women with pre-existing diabetes be taking?

Answer 10

5mg of folate OD

75mg aspirin to avoid HTN and PET

Question 11

What changes should patients with pre-existing DMT1 or DMT2 expect for pregnancy?

Answer 11

• aim blood glucose at gestational GDM targets
• control T2 with insulin and metformin and stop other meds
• use capillary ketone strips if T1

Question 12

When should patients with pre-existing DMT1 or DMT2 deliver?

Answer 12

planned delivery between 37 and 38+6 weeks

T1 delivery: sliding scale of insulin and a dextrose and insulin infusion

Question 13

When should patients with GDM deliver?

Answer 13

they can give birth up to 40+6

Question 14

What extra check should pre-existing DMT1 or DMT2 get during pregnancy?

Answer 14

• retinopathy screening at 28 weeks

Question 15

What are babies of mother with diabetes at risk of?

Answer 15

• Neonatal HYPOGLYCAEMIA
• Polycythaemia (raised haemoglobin)
• Jaundice (raised bilirubin)
• Congenital heart disease
• Cardiomyopathy
• (macrosomia)

Question 16

What blood glucose should neonate be kept above?

Answer 16

aim for above 2mmol/L