Diabetes In Pregnancy

Question 1

It is classified as pre existing (type 1 or 2) or…

Answer 1

Gestational (GDM)

Question 2

Why is the incidence of GDM increasing?

Answer 2

Increasing levels of obesity and older women getting pregnant

Question 3

What complications can occur?

Answer 3

Hypoglycaemia unawareness (especially first trimester)
Increased risk of pre-eclampsia
4x increased risk of miscarriage
4-10x increased risk of congenital abnormalities (reduced with good glycaemic control)
Macrosomia or growth restricted
Pre term labour
C section rates high and operative delivery
Increased infection risk
Polyhydraminos

Question 4

Babies of diabetic mothers are more likely to develop…later in life

Answer 4

DM and obesity

Question 5

Is pregnancy already a diabetogenic state?

Answer 5

Yes - pregnancy itself promotes insulin resistance (ensure adequate nutrition for fetus)
If mother has DM, is obsess, has PCOS, the insulin resistance is even more so - need more insulin to compensate, but the pancreas may not be able to keep up, causing persistent hyperglycaemia

Question 6

What pre pregnancy care should be give to those with pre existing DM?

Answer 6

Aim for HbA1C <48mmol/L (6.5%)
If >86 strongly advise to avoid pregnancy
If BMI >27, suggest weight loss techniques
Offer retinal assessment - retinopathy can worsen in pregnancy
Renal assessment - calculate GFR and creatinine

Question 7

What medications should be started/stopped as part of pre pregnancy care for those with pre existing DM?

Answer 7

Folic acid 5mg/day 3 months preconception and 3 months post
Aspirin 75mg > 12 gestation to reduce pre-eclampsia risk
LMWH may be needed
If BMI > 35 start vitamin D supplements
Stop unsafe medication - statins, ACEi, ARBs
Metformin can be continued, but other hypoglycaemics stopped and substituted with insulin if appropriate

Question 8

Will more or less insulin be needed during pregnancy?

Answer 8

More, insulin needs increase by 50-100% as pregnancy progresses

Question 9

How should those with pre existing DM be managed during pregnancy?

Answer 9

Blood glucose targets:
Pre meal <5.3
1 hour post meal < 7.8
2 hours post meal < 6.4

USS:
Dating 12 week (neural tube defects)
Detailed anomaly scan at 18-20weeks
Growth and liquor monitored every 4 weeks from 28 weeks

Joint obstetric-DM clinic 1-2 weekly
Repeat retinal assessment at 28 weeks (or earlier if abnormality in first)

Question 10

What congenital abnormalities are associated with pre existing DM?

Answer 10

Cardiac - VSD, ToGA, ToF, truncus arteriosis, persistent fetal circulation
CNS - anencephaly, spina bifida, hydrocephaly
MSK - caudal regression/ sacral agenesis (associated with insulin dependent DM and insufficient folic acid)

Question 11

How do those with sacral agenesis present?

Answer 11

Small pelvis

Neurogenic bladder

Question 12

When should those with pre-existing DM deliver?

Answer 12

37-38+6

Either IOL or elective CS - elective at 38-39 weeks

Question 13

What is gestational diabetes?

Answer 13

Carbohydrate intolerance that develops for the first time in pregnancy
Affects 1 in 7 births

Question 14

What risk factors are there for GDM?

Answer 14

BMI>30
Previous GDM
Previous macrosomic baby >4.5kg
First degree relative with DM
Family origin with high prevalence of DM - South Asia, black Caribbean, Middle Eastern

Question 15

Those with RFs for GDM should be screened for it, how is this done?

Answer 15

Oral glucose tolerance test
Done at 26-28 weeks, unless previous GDM - at 16-18 weeks
Take high load (75g) glucose gel and measure glucose before and after to see if appropriate response

Question 16

What is the diagnostic threshold for GDM?

Answer 16

Fasting >5.6

2hour post >7.8

Question 17

What is the most frequent complication of GDM?

Answer 17

Macrosomia

Question 18

How is GDM managed?

Answer 18

First line= lifestyle management via diet and exercise
Regular glucose testing
If targets not met within 1-2 weeks, metformin should be started
Offer glibenclamide to women who cannot tolerate metformin or fail to meet targets with metformin but refuse insulin
If glucose targets not met with metformin, offer insulin

Question 19

If at the time of diagnosis, the fasting glucose level is above 7, what should be offered?

Answer 19

Insulin

Question 20

In those with GDM, when should delivery occur?

Answer 20

Uncomplicated: 39-40+6

Question 21

What postnatal GDM management should be offered?

Answer 21

Stop all treatment and BG monitoring at delivery
Check blood glucose at 6-13w postpartum
HbA1C at 13w and yearly thereafter
50% develop DMT2, so give lifelong dietary advice and follow up