Gestational Diabetes

Question 1

Dx of diabetes in pregnancy

Answer 1

Fasting >/= 7mmol/L
1hr not used
2hr >/= 11/1mmol/L
Random >/= 11.1 mol/L
HbA1c >/= 48mol/mol or 6.5%

Question 2

Discharge requirement for GDM

Answer 2

Advice on benefit of optimising post part + inter pregnancy wt
Recommend OGTT at 6-12 wk post part to screen for persistent diabetes
Recommended lifelong screening for diabetes at least every 3yrs
Early glucose testing in future pregnancy

Question 3

Postpartum care of GDM

Answer 3

Cease metformin +/or insulin immediately after birth
Monitor - QID for 24 hr with target = 7.
If normal stop after 1 day.
/= 7 mol/L RV and BGL monitoring. Insulin rarely needed but if needed start low.
If diet controlled no postpartum monitoring needed
Routine care needed
Breastfeeding - support and encourage lactation support. Metformin + insulin are safe for BF.
Newborn - Keep warm. Early feeding with in 30-60 mins if good feed then BGL before 2rd feed or within 3 hrs of birth. If not feeding effectively then BGL at 2 hr. BGL every 4-6 hrs prefers until monitoring ceases.

Question 4

Mx of GDM in intrapartum care. Vaginal vs CS

Answer 4

Vaginal - both spontaneous or IOL. Cease metformin and insulin when labour start. If IOL in morning and on insulin. pt is asked to use rapid in the morning but not long acting. If afternoon thengive usual meal time and bed time insulin.
Elective CS - Day before stop metformin 24 hr prior. Give insulin the night before procedure. Day of a mane procedure - fast from midnight. omit mane insulin.
Monitor BGL 2/24 >7 reassess in 1hr or insulin infusion.

Question 5

Birth timing options and mode for GDM

Answer 5

Timing
- Diet controlled with no fetal macrosomia of other cx = SVB
- Suspected fetal macrosomia or other Cx = IOL at 38-39 wk
- Not base on symptoms/macrosomia or Cx
Mode of birth
- 4500g = CS
If 4000-4500g consider other individual factor e.g. maternal status, ob Hx, birth Hx, previous marcosomia +/- SD.

Question 6

Insulin use in GDM

- when and how

Answer 6

Indication - hyperglycaemia despite optimisation of non drug therapy or suboptimal BGL or material preferences.
AE - hypoglycaemia, local allergic reaction, systemic reaction e.g. skin eruptions, oedema
Commencement - endocrine referral, R/V with in 3 days
Titration - Increase insulin resistance in 3rd trimester but plateau by 36-38 wk. Dose titrated every 2-3 day by 2-4 unit but no greater 20%

Question 7

Types of insulin to use

Answer 7

Types - Increase fasting glucose - single note inject of intermediate onset 1.5hr, peak 4-12 hr and duration 24hrs.

• If post prandial increase glucose - meal time rapid acting with onset 10-20 mins, peak 1-3hr duration 3-5 hrs
• Or Both - basal bolus insulin regimen. Mealtime rapid insulin and intermediate acting or twice daily mixed insulin if women is reluctant to inject 4 x day, onset 30min, peak 2-12 hr, duration 24 hrs

Question 8

Metformin use in GDM

Answer 8

Indication - 1 week of elevated BGL despite Diet or macrosomia AC >75% tile at Dx.
AE - Nausea, loss of appetite, diarrhoea, vomiting, reduced serum bit B12, may associated with preterm birth

Question 9

Antenatal care for GDM

Answer 9

MDT
increased Monitoring- If dx before 16/40 or suboptimal BGL or there Cx e.g. HTN, preeclampsia, macrosomia, IUGR.
Maternal Wt -

Question 10

Diagnosis of GDM

Answer 10

1 or more of the following on a OGTT
Fasting >/= 5.1-6.9mmol/L
1 hour >/= 10mmol/L
2 hour >/= 8.5-11 mol/L
or 
HbA1c - 1st trimester only >/= 41-48 or 5.9%

Question 11

Screening for GDM

Answer 11

OGTT 75 g
If RF present 1st trimester then at 24-28 as well otherwise just 24-28 wks
Advise women to fast expect for water for 8-14 hrs
Take usual medication

Question 12

Short term and long term complications of GDM for the mum

Answer 12

Short term - pre eclampsia, induced labour, operative birth, hydramnios, postpartum Haemorrhage, infections
Long term - Recurrent GDM in subsequent reg, progress to T2D, development of CVD

Question 13

Short term and long term complications of GDM for the fetus

Answer 13

Short term - RDS, Jaundice, hypoglycaemia, premature birth, hypocalcemia, polycythaeia, LBwt and adiposity. Macrosomia = shoulder dystocia - > CS birth. Bone fracture , nerve palsy, hypoxic ischaemic encephalopathy
Long term - Ipaired glucose tolerance, development of T2D, obesity, no evidence that current tx reduces long term consequences.

Question 14

Pathogenesis of GDM

Answer 14

Anti insulin factors produced by placenta and high maternal cortisol levels create increase peripheral insulin resistance -> higher fasting glucose -> leading to GDM and or exacerbation of pre existing D

Question 15

Risk factors for GDM

Answer 15

BMI >30 pre-pregnancy
Ethnicity - Asian, Indian subcontinent, aboriginal, TSI, middle eastern.
Previous GDM
Previous elevated BGL
Maternal age > 40 yr
FmHx DM (1st degree relative or sister with GDM)
Previous macrosomia BW >4.5kg or 90% tile
Previous perinatal loss
PCOS
Med- corticosteroids, antipsycotics
Multiple pregnancy

Question 16

Different mx of Diet controlled vs well controlled with insulin and poor control with insulin/fetal macrosomia

Answer 16

Diet controlled: Risks similar to general obstetric population, fetal growth scan for clinical reason and await spontaneous labour
Well controlled with insulin: intermediate risk, renal growth scan at 34-36 weeks, deliver at 38 wks.
Poor control with insulin/fetal macrosomia: High risk, fortnightly fetal growth scans, deliver at 38 wks

Question 17

Effects of Glucose in pregnancy

Answer 17

Major cardiac anomalies
Neural tube defects
Sacral genesis
Risk relates to pre conceptual HbA1C
Doubled risk even if HbA1C normal
16% risk for HbA1c > 10%

Question 18

Presentation of Type 1 diabetes in pregnancy

Answer 18

- Early pregnancy vomiting - Diabetic ketoacidosis
Hypoglycaemia - Collapse/death
Progression of retinopathy
Progression of renal impairment
Autonomic neuropathy, gastroparesis

Question 19

Presentation of Type 2 diabetes in pregnancy

Answer 19

Comorbidities:
Obesity
Vasculopathy
 Advanced maternal age 
Hyperlipidaemia

Question 20

Mx of Type 1 and 2 diabetes who want to become pregnant or who is pregnant

Answer 20

Counsel regarding risks/mode of care – hospital care with diabetes team
Address lifestyle factors – smoking/alcohol
Folate and iron - high dose folate 5mg/day
Pregnancy screening bloods
Pap smear and routine screening
Refer to endocrinologist/complications review including eyes
Baseline investigations – HbA1c, PET bloods, urinary protein
Discuss timing of trying to conceive and contraception
QID BSL’s
Increased doses insulin
Basal bolus insulin OR insulin pump
Baseline blood pressure/renal function/urine protein
Eye review/complications review
Screening for major fetal anomalies
Regular growth scans
Insulin infusion in labour