GDM

Question 1

What is GDM (+ pathophysiology)

Answer 1

Gestational Diabetes
Occurs in 2-5% of pregnancies
Glucose intolerance during pregnancy

In pregnancy, hormones such as human placental lactogen and oestrogen cause the placenta to secrete adipokines that increase insulin resistance in the maternal body. This increases blood glucose levels to increase glucose supply to the foetus. The pancreas compensated for high blood glucose in the maternal body by increasing glucose production.
In GDM, this becomes dysregulated and the pancreas doesn’t produce enough insulin - causing hyperglycaemia.
The foetus also has to produce more insulin to manage the foetal hyperglycaemia -> causing macrosomia and neonatal hypoglycaemia.

GDM usually resolved after delivery but does increase long term risk of T2DM

Question 2

Risk factors for developing GDM

Answer 2

BMI >30
Previous macrosomic baby (>4.5kg)
Previous GDM
FHx of diabetes
Ethnicity with higher risk of diabetes (e.g., south Asian, Afro-Caribbean)

Question 3

GDM presentation

Answer 3

Often asymptomatic and picked up during screening and check-ups

Symptoms can include:
Polyuria
Polydipsia
Lethargy
Dry mouth
Visual disturbances (due to temporary hyperglycaemia)

Note - PCOS can present with insulin resistance

Question 4

Diagnosing GDM

Answer 4

Glycosuria
OGTT (oral glucose tolerance test)

Diagnosis is given if:
fasting plasma glucose >5.6
2-hour plasma glucose >7.8

Question 5

Antenatal management of GDM

Answer 5

At home BG monitoring (4-6 times a day)
Frequent follow-up to adjust treatment and manage complications

If fasting BG at diagnosis is 5.6-7
1st - try patient education and lifestyle changes for 2 weeks
2nd - If after 2 weeks BG still high - start metformin
3rd - If BG still high - Insulin (basal-bolus routine)

If fasting BG at diagnosis is >7
1st - Insulin (basal-bolus routine)

Question 6

Intrapartum management of GDM

Answer 6

Intrapartum care -
Continuous foetal monitoring
Plan for potential complications/ section (e.g. large for gestational age

Question 7

Postpartum management of GDM

Answer 7

Maternal:
- Stop medications and monitor for persistent hyperglycaemia before discharge
- Repeat fasting BG 6-13wks
- Annual HbA1c monitoring

Neonatal:
- monitor BG in first few hours, feed within 30mins + every 2-3hrs (BG aim >2)
- Only discharge after 24hrs, have stable BG, feeding adequately
- Check for signs of complications e.g., congenital heart disease/ cardiomyopathy/ hypoglycaemia, respiratory distress/ jaundice

Question 8

Complications if GDM for the pregnant person

Answer 8

Risk of PIH/ pre-eclampsia
Caesarean delivery (e.g., because of macrosomia)
T2DM
Higher risk of GDM in the future

Question 9

Complications if GDM for the baby

Answer 9

Macrosomia (large for gestational age/ >4.5kg at birth) -> risk of shoulder dystocia
Neonatal hypoglycaemia (first 48hrs)
Metabolic syndrome (higher risk of obesity and T2DM)
Still birth (more a risk of BG is poorly controlled)