Gestational Diabetes Flashcards
When is the most common time to develop GDM?
3rd trimester
But can happen at any point
How can GDM affect pregnancy?
Macrosomia - secondary to all the sugar - anything over 8lb13oz/4kg - though don’t offer c-section routinely until larger than 5kg (risks of big babies include emergency c-section, shoulder dystocia)
Polyhydramnios - greater risks of premature birth and other delivery problems e.g. breech position
Preeclampsia
Premature birth
Neonatal hypoglycaemia and jaundice
Usually recommend giving birth before 40+6 irrespective of any known concurrent complications - may need induction
USS:
Wk 18-20 - abnormalities
Wk 28 + 32 + 36 - growth and amniotic fluid monitoring
From wk 36 - will likely want serial scans every 2-3wks until delivery
When is GDM screened for? What risk factors mean that someone is likely to be screened? How is it diagnosed?
During first antenatal appointment at 8-12wks - Hx for risk factors (prev G/DM, BMI >30, FHx, previous baby >4.5kg, rapid increase in foetal growth, polyhydramnios, PCOS)- if 1+ risk factors will be offered an oral glucose tolerance test (OGTT) for screening
OGTT:
Done at 24-28wks (unless had GDM before then offered at first appointment)
No food/drink for 8-10hrs (usually overnight) then morning blood test then given glucose drink then repeat blood test 2hrs later
Dx: (think 5678)
If initial BG is >5.6mmol
If 2hr post OGTT >7.8mmol
How should GDM be followed up postpartum?
Fasting glucose blood test 6-13wks post partum to see if T2DM has developed - >7mmol (as at an increased risk); may alternatively do HbA1C (>48mmol)
Also will be at an increased risk of developing GDM in future pregnancies so will be monitored more closely from outset - possible OGTT just after 12wks (though test still more sensitive when delivered between 24-28)
How do you monitor GDM during pregnancy? What are the target BGs?
Will be given a home glucose finger prick monitor
Blood sugars measured:
Before breakfast
One hour after each meal
Aim for BG levels of:
5.3 mmol/litre for fasting
7.8 mmol/litre 1 hour after meals, or 6.4 mmol/litre for 2 hours after meals.
HbA1C also monitored for any major deterioration (though becomes less accurate as pregnancy progresses)
Eye care:
Check for retinopathy at booking visit if already have DM, then repeat at 16wks + 28wks
USS for foetal growth:
20wks anomaly
28, 32, 36 growth scans then serially every c.1-2wks until delivery depending on plans/complications
How do you manage GDM?
1st line:
Healthy diet, starchy foods w/low glycemic index, fruit + veg, minimise sugar, lean proteins
Exercise - 150mins aerobic/wk + strength on 2+ days of wk
2nd line:
Add metformin - 500mg slow release with meals (up to 1g/day)
3rd line:
Add insulin - given if cannot tolerate metformin, sugars aren’t controlled with metformin, very high BG, baby is very large or polyhydramnios
What insulin regimens can be used in GDM?
Levomir:
Basal rate insulin for 24hr low level control
Start at night to treat early morning hypos
Novarapid:
Rapid acting
Given before meals that are causing spikes in BG
What neonatal monitoring is important postpartum in GDM?
Baby at risk of hypo due to massively sugar rich environment being changed to no sugar environment
BG every 2-4hrs - may need IV glucose
What is the typical delivery plan for people managing GDM with diet alone? Diet + metformin? Diet + metformin + insulin?
Diet - can usually let develop to 40wks
Metformin - probs induce at 39wks
Insulin - induce at 38wks (risk of miscarriage if left longer)
All these are rough guidelines and are subject to change depending on any concurrent maternal or foetal problems
What about diabetes before getting pregnant?
Get BMI + HbA1C down as best as possible
Get sugars controlled well
If poorly controlled - can worsen complications e.g. retinopathy, neuropathy and nephropathy
What other medicine should be prescribed in GDM?
Folic acid: 5mg OD (high dose)
Ideally from 3wks pre-conception to 12wks post (if known diabetes)
To reduce the risk of spina bifda
Aspirin: 75mg OD
From 12wks up until labour
To reduce the risk of preeclampsia (also given to those with CKD, SLE/antiphospholipid syndrome, Hx HTN in pregnancy)
What are the other indications for taking folic acidic pregnancy?
Every mother should be taking a low dose - 400mcg OD - before and during first 12wks of pregnancy when babies spine is developing; if not taking before, should take as soon as you find out you are pregnant
High dose - 5mg: FHx neural tube defects Previous baby with neural tube defect Diabetes Antiepileptic medication
What are some risks of GDM?
SMASH N
Shoulder dystocia Macrosomia Amniotic fluid excess Still birth Hypertensive disorders Neonatal hypoglycaemia
