Diabetes in Pregnancy

Question 1

Definition

Answer 1

• Can be pre-existing diabetes mellitus (type 1 or type 2)
• Gestational diabetes mellitus (GDM) = develops during pregnancy

Question 2

GDM aetiology

Answer 2

Insulin resistance due to hormonal changes
- Placenta produces human placental lactogen decreases body’s sensitivity to insulin
- Prolatin, growth hormone, progesterone Increased demand for insulin production

Question 3

Risk factors

Answer 3

Previous MHx gestational diabetes
Previous child born large: >4.5kg
Obesity: BMI>30
Ethnicity: South Asian, Afro-Caribean, Middle Eastern
Family history of diabetes

Advanced maternal age >40

Question 3

Signs

Answer 3

Large for dates uterus >90th percentile
Polyhyramnios
Glucose on urine dipstick (++)

Question 4

Symptoms

Answer 4

Polydipsia
Polyuria
Fatigue
Dry mouth
Blurred vision

Question 5

Diagnosis 5,6,7,8

Answer 5

• OGTT at 24-28 weeks gestation > 7.8 mmol/L = diagnostic
• Fasting glucose >5.6 mmol/L = diagnostic
• HbA1c testing: monitor blood glucose in women with pre-existing diabetes
• Fetal USS
• Urine dip

Question 6

Treatment

Answer 6

Fasting blood glucose < 7.0 mmol/L: Lifestyle modifications is FIRST LINE
- SL oral anti diabetic agents: Metformin or Glibenclamide (sulfonylurea) = used when FL is insufficient after 1-2 weeks
- TL Insulin therapy: Rapid-acting insulin. However, insulin is offered immediately if BG > 7.0 mmol/L or in any Px with GDM who has obstetric complications.

Fasting glucose above 6 mmol/l plus macrosomia (or other complications): start insulin ± metformin

Question 7

Monitoring blood glucose levels

Answer 7

The NICE (2015) target levels are:
- Fasting: 5.3 mmol/l
- 1 hour post-meal: 7.8 mmol/l
- 2 hours post-meal: 6.4 mmol/l
- Avoiding levels of 4 mmol/l or below

Women with existing type 1 and type 2 diabetes should aim for the same target insulin levels as with gestational diabetes.

Question 8

Pre-existing diabetes extra screening…

Answer 8

• Should take 5mg folic acid from preconception until 12 weeks gestation
• Retinopathy screening should be performed shortly after booking and at 28 weeks gestation = risk of rapid progression of retinopathy

Question 9

Planned delivery

Answer 9

GDM: Up to 40 + 6 weeks
Pre-existing diabetes: 37 and 38+6 weeks

Question 10

What is a sliding insulin regime?

Answer 10

Considered during labour for women with T1DM. A dextrose and insulin infusion is titrated to blood sugar levels, according to the local protocol. This is also considered for women with poorly controlled blood sugars with gestational or type 2 diabetes.

Question 11

Complications during pregnancy (SHAME)

Answer 11

Shoulder dystocia
Hypoglycaemia in neonate
Amniotic fluid excess: polyhydramnios
Macrosomia
Early birth: preterm labour

Question 12

Babies of mothers with diabetes are at risk of:

Answer 12

Neonatal hypoglycaemia
Polycythaemia (raised haemoglobin)
Jaundice (raised bilirubin)
Congenital heart disease
Cardiomyopathy

Question 13

Treatment of neonatal hypoglycaemia

Answer 13

Aim: maintain blood sugar above 2 mmol/l,
- if it falls below this = IV dextrose of nasogastric feeding.

Question 14

Post natal care

Answer 14

GDM: can stop diabetes meds immediately after birth and follow-up fasting glucose after min 6 weeks
Pre-existing diabetes: Lower insulin doses and be wary of hypoglycaemia in postnatal period as insulin sensitivity will increase with birth and breastfeeding.