Diabetes in Pregnancy

Question 1

What happens to insulin resistance in pregnancy?

Answer 1

• Insulin resistance increases throughout pregnancy
  
  • Increase dose of metformin or insulin during pregnancy for those with DM
• Hypoglycaemia is more common in pregnancy → is very dangerous to mum and baby
• Postnatally, insulin requirements return to normal levels, so insulin should be adjusted accordingly

Question 2

What are the effects of pregnancy on diabetes?

Answer 2

• Nausea and vomiting - especially 1st trimester
• Greater importance of tight glucose control
• Increased insulin requirements in second half of pregnancy
• Increased risk of severe hypo
• Retinopathy
• Nephropathy

Lesser effect in Gestational vs Mellitus

Question 3

What are the effects of diabetes on pregnancy?

Answer 3

• Increased risk of
  
  • Miscarriage
  • Congenital malformation
  • Macrosomia
  • Pre-eclampsia
  • Stillbirth
  • Infection
  • C-section

Lesser effect in Gestational vs Mellitus

Question 4

What is the diagnosis is glucose drops with insulin treatment in pregnancy?

Answer 4

• Placental Failure
  
  • Human placental lactogen & steroids drive diabetes in pregnancy → if insulin control gets better the placenta isn’t working as well
  • Doppler USS will not detect this as it is a metabolic change
  • Check foetal movement and CTG measurements.

Question 5

What is the pre-conception counselling for women with DM?

Answer 5

• Pre-conception counselling
  
  • Miscarriage risk is higher
  • Poor glycaemic control is teratogenic
  • Stillbirth risk - baby outgrows placental supply
  • Polyhydramnios - baby has osmotic diuresis → cord prolapse & placental abruption
  • Hypoglycaemic risk for baby after cut cord as loss of glucose and high insulin levels
  • Infection
  • DKA
• Pre-conception checks → tell them to use contraception until these are checked!
  
  • Glucose control must be tight (use a 4-hour diary) – test HbA1c for risk level
  • Renal testing (U&Es, creatinine)
  • BP checks
  • Retina checks
  • Stop any statin use and start high dose folic acid (5mg, OD) until 12w gestation

Question 6

What mechanism causes macrosomic babies in women with diabetes?

Answer 6

1. If mother has high glucose, the glucose passes to the baby
2. Baby’s pancreas produces insulin (like IGF-1, a growth factor)
3. Baby becomes macrosomic (insulin and fragmin are the two molecules that cannot cross the placenta)

Question 7

What is the management of DM in pregnancy?

Answer 7

• Additional Insulin or Metformin/usual medication
• Blood glucose monitoring:
  
  • Fasting blood glucose target: <5.3mmol/L
  • 1-hour postprandial target: <7.8mmol/L
  • HbA1c can be used to assess the level of risk in the pregnancy
• Timeline of contacts:
  
  • 12w “booking” checks
  • 20w “anomaly” scans
  • 28w, 32w, 36w - Foetal surveillance
  • Extra joint antenatal-diabetes clinics every 2 weeks
• Induction or ELCS at 37+0 to 38+6w
• If antenatal corticosteroids are needed, additional insulin therapy is required to maintain normoglycaemia

Question 8

Define Gestational Diabetes.

Answer 8

New-onset diabetes during pregnancy that usually disappears after birth.

• Occurs 24-28w gestation

Question 9

What are the risk factors for Gestational Diabetes?

Answer 9

• BMI >30
• Previous GDM
• Previous baby weighing ≥4.5kg
• Asian ethnicity
• FHx (1st degree) of diabetes

Question 10

What are the appropriate investigations for suspected gestational diabetes?

Answer 10

• Glycosuria on urine dipstick, Previous GDM or Risk factor on clerking → 2-hour 75g OGTT (immediate ± HbA1c testing for pre-existing DM, check again at 24-28 weeks)
• Diagnose if - “5, 6, 7, 8”:
  
  • Fasting plasma glucose >5.6 mmol/L
  • 2-hour OGTT >7.8 mmol/L
  • If diagnosed, offer a review at a joint diabetes and antenatal clinic within 1 week

Question 11

What is the management of gestational diabetes in pregnancy?

Answer 11

• 1st line (if fasting blood glucose <7mmol/L) = Changes in Diet and Exercise
• 2nd line = Metformin + CDE
  
  • If metformin is contraindicated, go straight for insulin
• 3rd line (if 2nd line ineffective or >7mmol/L) = Insulin, Metformin + CDE
• 4th line = Glibenclamide
• Blood glucose monitoring daily
  
  • Pre-meal/fasting target: <5.3mmol/L
  • 1-hour postprandial target:<7.8mmol/L

Question 12

What is the management of diabetes in labour and delivery?

Answer 12

• Delivery = Offer IOL or ELCS between 37+0w and 38+6w → no later than 40+6w
• Monitor capillary glucose every hour during labour (maintain 4-7 mmol/L)
• Discontinue/Lower blood glucose lowering treatment immediately after birth

Question 13

What is the management of diabetes postpartum?

Answer 13

• GP should perform a fasting plasma glucose at 6-13w post-partum (i.e. at 6w post-natal check)
  
  • <6.0mmol/L = low probability of diabetes, need an annual test, moderate risk of developing T2DM
  • 6.0-6.9mmol/L = high risk of T2DM
  • >7.0mmol/L = 50% chance of having/developing T2DM → offer diagnostic test to confirm