Diabetes in pregnancy

Question 1

What are the two most common medical disorders complucating pregnanies?

Answer 1

1. Hypertension
2. Gestational diabetes - ~4% affected

Question 2

How common is gestational diabetes?

Answer 2

Complicates up to 1 in 20 pregnancies

• 87.5% have gestational diabetes
• 7.5% have type 1 diabetes
• 5% have type 2 diabetes

Question 3

What are the risk factors for GD?

Answer 3

• age
• FH or PMH
• BMI >30kg/m2
• multiple pregnancy
• Previous macroscopic baby weighing >4.5kg
• South Asian, clack Caribbean, Mddle Eastern ackground

Question 4

What is the aetiology of GD?

Answer 4

Insulin resistance increases during pregnancy - worst in 3rd trimester

Large demand for insulin cannot be met by pancreatic beta-islet cells

Question 5

How is gestational diabetes diagnosed?

Answer 5

75g 2 hour oral glucose tolerance test (OGTT)

Diagnose gestational diabetes if the woman has either:

• a fasting plasma glucose level of 5.6 mmol/litre or above or
• a 2‑hour plasma glucose level of 7.8 mmol/litre or above

Question 6

If a patient has had previous gestational diabetes, when should you test for this?

Answer 6

OGTT at 16 weeks

If normal then repeat at 24-28 weeks gestation

Question 7

If the patient has not previously had gestational diabetes, when should you test for it?

Answer 7

28 weeks - if risk factors present now and no Hx of previous gestational diabetes

Question 8

What is the antenatal management of gestational diabetes in terms of follow-up?

Answer 8

Offer review with joint diabetes and antenatal clinic within a week of diagnosis

Clinics should stay in contact with patient every 1-2 weeks throughout pregnancy

Question 9

How often must the patient monitor their glucose in GD?

Answer 9

T2DM/GD managed on multiple daily insulin injection regimen:

1. Fasting
2. Pre-meal
3. 1 hour post meal
4. Bedtime

T2DM/GD managed with diet and extercise changes alone, oral therapy or single dose insulin:

1. Fasting
2. 1 hour post meal

Question 10

What are the glucose level targets in a pregnant patient with GD?

Answer 10

fasting: 5.3 mmol/litre

1 hour after meals: 7.8 mmol/litre or

2 hours after meals: 6.4 mmol/litre.

Question 11

How do you monitor the fetus in GD in pregnancy?

Answer 11

Serial growth scans every 4 weeks from 28-36 weeks gestation

Question 12

What is the management of a new diagnosis of GD?

Answer 12

All:

• See patient within a week in joint diabetic and antenatal clinic
• Diet and exercise advice
• Self-monitoring glucose

If fasting <7mmol/L:

1. Trial of diet and exercise for 1-2 weeks
2. If unsuccessful, start metformin
3. If targets still not met, add insulin (short-acting)
   
   1. If insulin declined or metformin not tolerated/unsuccessful, offer glibenclamide

NB: BUT if <7 mmol/L and scans show macrosomia or hydramnios, then start insulin.

If fasting is 7 or >7mmol/L:

1. Start insulin

Question 13

What type of insulin is used in GD?

Answer 13

short-acting only

Question 14

What preparations should be made for delivery in a patient with GD?

Answer 14

Elective birth no later than 40+6 weeks gestation (i.e. <41 weeks)

Question 15

What changes should you make if a diabetic patient becomes pregnant in terms of medication? What lifestyle advice should be offerred?

Answer 15

Weight loss if BMI >27kg/m2; tight glycaemic control reduces complication rates.

Stop oral hypoglycaemics (except metformin) + start insulin

Folic acid 5mg/day - preconception to 12 weeks gestation

Question 16

What complication of previous diabetes can deteriorate during pregnancy?

Answer 16

Retinopathy - should be treated as can worsen during pregnancy

Question 17

Which scan should be detailes in a patient with pre-pregnancy diabetes diagnosis?

Answer 17

Anomaly scan at 20 weeks should be detailed including four-chamber view of the heart and outflow tracts

Question 18

How long should you manage the GD once baby is delivered?

Answer 18

Discontinue treatment immediately

But monitor for new diagnosis of diabetes - fasting blood glucose at 6-13 weeks OR HbA1c after 13 weeks.

Remember to offer OGTT early in subsequent pregnancies (ASAP after booking and again at 24-28 weeks)

Question 19

When should you suspect T2DM postnatally after GD diagnosis?

Answer 19

Suspect if fasting glucose at 6-13 weeks is _>_7mmol/L; offer diagnostic test.

Fasting blood glucose test 6-13 weeks:

_<_6 mmol/L - mod risk of T2DM, annual HbA1c and lifestyle advice

6-6.9 mmol/L - high risk of T2DM, annual HbA1c and lifestyle advice

_>_7 mmol/L - T2DM likely at present, offer diagnostic test

Question 20

What are the complications of untreated GD?

Answer 20

Maternal:

• HTN disease
• Traumatic delivery
• Stillbirth

Foetal:

• Macrosomia
• Neonatal hypoglycaemia
• Congenital abnormalities

Question 21

How do you counsel a patient about GD?

Answer 21

Common condition affecting 4% in pregnancy

Cause: pancreas cannot make enough insulin to meet increased demands

RF: age, FH, PMH, BMI, Asian

Complications if untreated: big baby, baby can have low blood sugar levels when born, abnomalities on scan and you can get high BP and traumatic delivery with risk of stilbirth.

Treatment: (depends but if <7mmol/L fasting then) lifestyle advice incl eating foods with low glycaemic index and exercising e.g. 30min walk after food. Referral to dietician for advice. If this doesn’t work then medication. You will also need to monitor blood glucose levels using a skin prick (incl fasting, 1hr post-meal and before bed)

Prognosis: GD is likely to occur in subsequent pregnancie (about 1 in 2 chance). Over 10 years, >50% develop T2DM.