Diabetes in Pregnancy Flashcards
(45 cards)
Different categories of diabetic patients you may encounter in antenatal clinic
- Pre-existing
- T1DM
- T2DM
- MODY, LADA
- Pre-diabetes/impaired glucose tolerance
- Gestational diabetes
Pre-diabetes/impaired glucose tolerance - HbA1c criteria for this category at booking/non-pregnant
HbA1c 41-49
(In NZ HbA1c cut off = 50 is diagnostic for diabetes in a non-pregnant patient)
Appropriate for direct referral to ADHB diabetes in pregnancy clinic
Definition of Type 1 Diabetes (1A and 1B)
Insulin deficiency
- Due to destruction of pancreatic ß-cells
Type 1a
- Autoimmune destruction
- Positive for antibodies to islet cells, GAD (Glutamic acid decarboxylase), insulin & tyrosine phosphatases
Type 1b: idiopathic therefore no antibodies
Type 2 diabetes - definition
Insulin resistance/deficiency through environmental (diet, lifestyle) or genetic factors (FHx, ethnicity)
Definition of LADA
Latent Autoimmune Diabetes in Adults
Predominantly in Scandinavian populations with variable titres of autoantibodies
Definition of MODY, mode of inheritance, number of subtypes
Mature Onset Diabetes of the Young
- Non-insulin dependent diabetes
- Diagnosed <25yo
- Autosomal dominant inheritance
- No antibodies
- Diagnosed by genetic testing. Subtypes defined by specific genetic defects – MODY 1-6
Gestational diabetes definition, incidence in pregnancy
Impaired glucose tolerance of variable severity, which either develops during, or is first recognised, in pregnancy
15% incidence in pregnancy
50g polycose test: what kind of test is this? Rate of false negative?
Screening test, 25% false negative rate, therefore should only be offered to low risk women
However should still discuss polycose vs OGTT with low risk women - they may prefer to have the diagnostic test instead
Polycose: criteria for a positive screening test
I hr glucose >11.0mmol/L, refer straight to
diabetes clinic
1 hr glucose 7.8-11.0mmol/L, 75 g
OGTT within a week
Timing of OGTT in pregnancy, and diagnostic criteria
24-28 weeks (24 in women with RFs)
75g glucose challenge
Fasting ≥ 5.5 mmol/l, or
2 hour glucose ≥ 9.0 mmol/L in NZ (8.5 in Aus)
GDM risk factors
Pre-existing
- Prev GDM, macrosomia, PET, unexplained perinatal loss/pre-term birth
- PCOS
- Obesity
- Age
- Ethnicity (Asian, Hispanic, Pacific)
- Chronic hypertension
- Steroid or antipsychotic medications
- Family history of diabetes
This preg:
- Booking HbA1c borderline
- Multiple pregnancy
- Macrosomia
Pre-existing diabetes: pre-pregnancy. Assess diabetes control: history/exam/investigations
Discuss contraception. Planning pregnancy? When? Discuss assessing and optimising diabetes control and lifestyle factors prior to pregnancy to reduce pregnancy risks
Type of diabetes, duration
Glycaemic control
Type of medication (metformin, insulin, sulfonylureas) - are these ok for pregnancy
Known diabetic complications (nephropathy, retinopathy, HTN)
Other RFs: age, other medical
conditions, past obstetric history
Weight, BP
Investigations:
- HbA1c
- U+E, creatinine, LFTs, FBC ferritin, TFTs, lipids
- If renal impairment: K+, Ca2+, phosphate, albumin and urea
- B12 if vegetarian
- Vitamin D if RFs for deficiency (coeliac, very pale skin,
no sun exposure, and women with darker skin (include all Indian women, as very high rates
of vitamin D deficiency)
- MSU, urine dip - ACR if proteinuria
- Booking bloods
- Check smears UTD
- Chase last eye screening
- ECG if high risk of cardiovascular complications: > 10 years (discuss), age > 40/45, younger age if
other risk factors such as smoking, plus obesity
T1 DM - additional pre-pregnancy investigations?
Thyroid antibodies for type 1: every 2 years if negative. If positive, no need to repeat
Coeliac screen for type 1: every 2 - 5 years if negative. If positive, may require referral for
endoscopy and biopsy to confirm diagnosis
Pre-existing diabetes, pre-preg or early pregnancy: medication counselling
Metformin - ok to continue Insulin - continue Sulfonylureas - stop, change to insulin Statins - stop Antihypertensives - ideally switch pre-preg to a pregnancy-friendly agent. If found out pregnant and was on ACE-inhibitor first trimester, still ok but switch to another agent ASAP
Pre-preg: high dose folic acid 5g at least 6 weeks pre-conception, and throughout the pregnancy
Iodine 150mcg throughout pregnancy
Consider low dose aspirin from 12 weeks (ideally start week 12-16, but up to 20 ok) and Ca supplementation
Pre-existing diabetes: trend in insulin requirements in first and second trimester? (from ADHB guideline)
Typically in first trimester, insulin requirements might increase, especially overnight in very early pregnancy
However between 9 - 13 weeks requirements usually decrease significantly, as women are more
insulin sensitive and hypoglycaemia can be a problem
16 - 20 weeks, women usually become more insulin resistant. Encourage women to increase their insulin doses adequately, especially mealtime boluses,
which typically increase more than the basal insulin (often end up with 2/3 insulin as bolus, 1/3
basal).
Many women fall behind with their treatment between 20 - 28 weeks’ gestation
Pre-existing diabetes: Hypoglycaemic unawareness may occur with tighter control. What advice to give to women about hypoglycaemia?
- BSL 5 before they drive
- Not to drive within 45 minutes of treating hypoglycaemia
- Ensure glucagon has not expired
- Recommend MedicAlert bracelet
Diabetes in pregnancy - timing of growth scans in third trimester?
28 and 36 weeks gestation, plus others as indicated
for obstetric concerns
Diabetes in pregnancy: general advice and goals for pregnancy
- Achieve normoglycaemia
- Prevent ketosis (DKA can occur more rapidly with high mortality and intellectual effect on offspring)
- Discuss adequate weight gain
- Dietician input
Timing of repeat HbA1c in pregnancy
HbA1c at 28 and 36 weeks with routine bloods
May do at 16 - 20 weeks as well in pre-existing diabetes
BSL testing timing and targets: GDM, T2DM, T1DM
GDM and T2: QID
- Fasting aim
Diabetes caloric requirements - ratio of carbs/fat/protein etc
Dietary composition is usually recommended as
18 - 20% protein
< 10% saturated fat, < 10% polyunsaturated fat
60 - 70% monounsaturated fat and carbohydrate
Indications to avoid or cease metformin?
- Significant fetal growth restriction reflecting a probable placental problem (all right to use if constitutionally small fetus)
- Ongoing maternal weight loss
- Maternal contra-indications such as sepsis, significant GI upset,
preeclampsia, renal failure or conditions that put women at risk of lactic acidosis
Maternal risks of diabetes in pregnancy
REMEMBER: different risk profiles for leaner and obese women, and for poor/good control
- Increased risk of miscarriage with increasing peri-conceptual hyperglycaemia
- Hypertensive disorders/preeclampsia
Risk PET with GDM are 3 - 5%
Risk PET with T1: up to 15 - 20% Good diabetes control reduces the risk of preeclampsia. - Operative delivery
- Birth trauma
Fetal risks of diabetes in pregnancy
REMEMBER: different risk profiles for leaner and obese women, and for poor/good control
- Polyhydramnios
- Macrosomia (particularly high post-prandial BSLs)
- Congenital abnormalities
(10% risk of abnormalities if HbA1c >100 at conception, if high risk get a tertiary anatomy scan) - IUGR with a raised HbA1c due to small placenta
- Preterm birth
- Birth trauma (shoulder dystocia)
- Perinatal mortality (particularly associated with abnormal fasting BSLs)
- Neonatal respiratory and metabolic complications (particularly associated with abnormal fasting BSLs)
- Increased risk to infant of obesity, diabetes, inattention/hyperactivity and impaired motor skills
