Diabetes in Pregnancy

Question 1

Why is pregnancy likely to trigger or worsen diabetes?

Answer 1

Diabetes mellitus may be a pre-existing problem or develop during pregnancy – gestational diabetes. Many pregnancy hormones are diabetogenic: Human placental lactogen, cortisol, glucagon, oestrogen and progesterone.

Question 2

What are the maternal complications of diabetes in pregnancy?

Answer 2

Maternal:
•	Preterm labour - 15%, associated with polyhydramnios
•	Pre-eclampsia 
•	UTI
•	Candidiasis 

Pregnancy also has an impact on diabetic complications
Increased risk of ketoacidosis, retinopathy, nephropathy and ischaemic heart disease.

Question 3

What are the foetal complications of diabetes in pregnancy?

Answer 3

Foetal:
• Miscarriage and Still birth
• Preterm labour
• Polyhydramnios - 25%, possibly due to foetal polyuria
• Macrosomia (although diabetes may also cause small for gestational age babies)
• Foetal hyperglycaemia (secondary to beta cell hyperplasia)
• Shoulder dystocia (may cause Erb’s palsy)
• Malformation rates increase 3-4-fold

Question 4

What are the neonatal complications of diabetes in pregnancy?

Answer 4

• Polycythaemia due to erythropoiesis: therefore, more neonatal jaundice
• Neonatal hypoglycaemia – removal of mothers glucose at birth and hyperinsulinemia
• Respiratory distress syndrome: surfactant production is delayed
• Hypomagnesaemia
• Hypocalcaemia

Question 5

What are the congential malformations that diabetes increases the risk of?

Answer 5

CVS
VSD
Transposition of the great arteries
Tetralogy of Fallot
Persistent foetal circulation 
Truncus arteriosus 

NTD
Spina bifida
Anencephaly

MS
Caudal regression
Sacral agenesis

Question 6

What steps should be taken prior to conception in a women with underlying diabetes?

Answer 6

• Weight loss for women with BMI of > 27 kg/m^2 Referral to dietician if needed
• Stop oral hypoglycaemic agents, apart from metformin, and commence insulin
• Check other medication suitable for pregnancy e.g. Statin and holoprosencephaly
• Check HbA1c levels – are they on target. If higher than 10% advise against pregnancy until they are reduced.
• Folic acid 5 mg/day from pre-conception until 12 weeks gestation

Question 7

What extra steps should be taken during pregnancy for women with underlying diabetes in pregnancy?

Answer 7

• Detailed anomaly scan at 20 weeks including four-chamber view of the heart and outflow tracts.
• Serial scan every 2-4 weeks for polyhydramnios and IUGR
• Tight glycaemic control reduces complication rates
• Monthly HbA1c checks during pregnancy

Delivery
• Deliver at 37-38+6 by IOL or elective C section if not naturally

Question 8

What are the blood glucose targets for a diabetic mother during pregnancy

Answer 8

Fasting 5.3 mmol/l

1 hour after meals 7.8 mmol/l

2 hours after meals 6.4 mmol/l

Question 9

What is gestational diabetes?

Answer 9

In pregnancy there is a progressive insulin resistance meaning more insulin is required to maintain blood sugar levels. If this requirement is not met you can develop GDM.

Question 10

What are the risk factors for developing gestational diabetes?

Answer 10

• BMI of > 30 kg/m²
• Previous macrosomic baby weighing 4.5 kg or above
• Previous gestational diabetes
• First-degree relative with diabetes
• Family origin with a high prevalence of diabetes (South Asian, black Caribbean and Middle Eastern)

Question 11

What are the symptoms of gestational diabetes?

Answer 11

Asymptomatic 
If present symptoms are the same as normal diabetes:
Polyuria
Polydipsia
Fatigue 
Retinopathies 
Proteinuria and glycosuria 
DKA

Question 12

How should suspected gestational diabetes be investigated?

Answer 12

Screening mainly by OGTT – fasting BG then 75g glucose then 2-hour BG

For women who’ve previously had gestational diabetes or are high risk, OGTT should be performed at booking or by 16-18 weeks after booking and at 24-28 weeks if the first test is normal.

NICE also recommend that early self-monitoring of blood glucose is an alternative to the OGTTs
Women with any of the other risk factors should be offered an OGTT at 24-28 weeks

Question 13

What are the diagnostic thresholds for gestational diabetes?

Answer 13

Diagnostic thresholds for gestational diabetes
These have recently been updated by NICE, gestational diabetes is diagnosed if either:

Fasting glucose is >/= 5.6 mmol/l
2-hour glucose is >/= 7.8 mmol/l

Question 14

After a diagnosis of gestational diabetes where should the mother be referred to?

Answer 14

Newly diagnosed women should be seen in a joint diabetes and antenatal clinic within a week. Women should be taught about self-monitoring of blood glucose.

Question 15

What diet advice should be given to women with gestational diabetes?

Answer 15

• Advice regarding diet (including eating foods with a low glycaemic index) and exercise should be given
• If the fasting plasma glucose level is < 7 mmol//l a trial of diet and exercise should be offered

Question 16

What drugs can be used to treat gestational diabetes and at what point are they required?

Answer 16

• If glucose targets are not met within 1-2 weeks of altering diet/exercise metformin should be started
• Glibenclamide should only be offered for women who cannot tolerate metformin or those who fail to meet the glucose targets with metformin but decline insulin treatment
Insulin
• If glucose targets are still not met insulin should be added to diet/exercise/metformin
• If at the time of diagnosis, the fasting glucose level is >= 7 mmol/l insulin should be started
• If the plasma glucose level is between 6-6.9 mmol/l, and there is evidence of complications such as macrosomia or hydramnios, insulin should be offered

Question 17

What are the delivery options for women with gestational diabetes?

Answer 17

If not delivered naturally by 40+6 weeks then then IOL or elective C section

Question 18

How should GDM be manage postnatally?

Answer 18

Stop all treatment and BG monitoring at delivery
Foetal and maternal BG at 6-13 weeks or HbA1c if not done by 13 weeks.

<6mmol/l = low risk but advice lifestyle modifications 
6-6.9mmol/l = high risk and advice lifestyle modifications and interventions 
>7mmol/l = they have T2DM and offer diagnostic testing

Maternal HbA1c at yearly there after