Diabetes in pregnancy Flashcards
Types of diabetes in pregnancy
- Pre-existing DM
- type 1 vs 2
- presents prior to onset of pregnancy - Gestational DM
- pre-existing DM vs true GDM
Gestational DM
Any degree of glucose intolerance with onset in pregnancy (2nd & 3rd trimester) and resolution within 6 weeks after delivery
- Pregnancy-induced insulin resistance mediated by pregnancy hormones
- NOT a/w fetal abnormalstes
- NOT a/w maternal end organ damage
Carbohydrate metabolism in pregnancy
Diabetogenic properties of pregnancy hormones: human placental lactogen, cortisol, estrogen, progesterone
-> affect pancreatic beta-cell function & peripheral tissue
sensitivity to insulin
-> Insulin sensitivity ↓ by 50-70%
-> state of insulin
resistance
-> ↑ insulin demand to maintain glucose homeostasis
Specific complications of pre-existing DM
Fetal:
1. Fetal Abnormalities
- Neural tube defect
- CVS abnormalities
- Sacral agenesis
- Caudal regression syndrome
2. IUGR (more common in women in T1DM compared to T2DM)
3. Prematurity
Maternal: Worsening of end organ diabetic complications
- Worsening of retinopathy
- Nephropathy
- DKA (Esp in T1DM with hyperemesis in pregnancy)
- Frequent UTI/ thrush
- HTN
+ ALL the complications due to GDM
Effects of maternal hyperglycaemia on the fetus
Due to facilitated diffusion, maternal hyperglycaemia leads to fetal hyperglycaemia
-> Stimulates fetal pancreatic beta-cell hyperplasia
-> Fetal hyperinsulinaemia
Fetal complications a/w Pre-Existing DM and GDM
- Macrosomia (Result of fetal hyperinsulinemia)
- Birth trauma
- Shoulder dystocia
- Caesarean delivery
- Prolonged labour - Polyhydramnios (Fetal polyuria)
- Stillbirth/Sudden intrauterine death
Pathophysio of fetal macrosomia
Fetal hyperinsulinemia
-> Promotes the growth of insulin-sensitive
tissue: adipose tissue, muscle, liver
-> disproportionate ↑ in size of trunk & shoulders (↑AC, ↓H/A ratio)
-> macrosomia
*Pedersen hypothesis
Neonatal complications a/w Pre-Existing DM and GDM
- Macrosomia
- excess fat deposits: chest, abdomen and scapula - SGA/IUGR
- mothers with chronic vascular cx of DM - Neonatal hypoglycemia (<2.6mmol/L in D1 of life)
- highest risk: first 3h of life
- resolves by 48h
- Sx: jitteriness, sweating, respiratory distress, apnoea, seizures, agitation - Neonatal hypocalcemia/ hypomagnesemia
- delayed maturation of parathyroid axis
- usually transient: 1st 24-72h of life - Hyperbilirubinemia (jaundice)
- Polycythemia
- venous hematocrit > ‘70%
- increased RBC mass
- increased viscosity: tissue hypo-perfusion, thrombosis, stroke
- Sx: plethoric, sluggish, lethargy - Respiratory distress syndrome
- insulin blunts maturational effects of cortisol towards surfactant production - Transient tachypnea of newborn
- CNS dysfunction (multifactorial)
- Perinatal asphyxia
- Glucose, electrolyte abnormalities
- Polycythemia
- Birth trauma - Spinal cord and brachial plexus injury during birth
- NICU admission
Long-term complications
12. Metabolic syndrome
13. Obesity
14. CVS disease
Respiratory distress syndrome in neonate
Hyperinsulinaemia affects pulmonary surfactant
production → delay pulmonary maturation
Maternal complications a/w Pre-Existing DM and GDM
- Preeclampsia/ Pregnancy-induced HTN
- Prolonged labour/ Traumatic delivery/ Operative delivery/ PPH
- Post natal complications
- Extended vaginal tears
- Wound complications
- Increased risk of T2DM (60%) and CVS disease
Screening of DM in pregnancy
Universal screening
- done at 26-28 weeks
- perform 75g 3-point OGTT
- do in 1st trimester if RFs present
Diagnostic criteria of 75g OGTT for DM in pregnancy
Fasting ≥ 5.1 mmol/L
1-hour ≥ 10 mmol/L
2-hour ≥ 8.5 mmol/L
Any 1/3 met = GDM
If fasting ≥7.0 or 2-h ≥11.1: suspect possible pre-existing DM
Risk factors of GDM
- Maternal age >35
- BMI >25
- FHx of DM
- Previous big baby >4 kg
- Previous still birth/ fetal anomaly
- Previous GDM
- PCOS
- Glycosuria
Can also be physiological (Blood volume increases during pregnancy → renal perfusion increases but kidney reabsorptive capacity remains the same → urine has glucose)
Management of GDM
- Multidisciplinary team management
- Diabetic nurse, Dietician, Obstetrician - Nutritional therapy FIRST
- Regular exercise as tolerated in pregnancy
- Patient education
- Monitor blood sugar profile more regularly
- 7 point blood sugar profile
- Before and after meals x3
+ before sleeping
(at least 2 days a week, consecutive days) - If dietary management cannot consistently maintain BSL within normal range -> Start insulin/metformin
- Start Aspirin prophylaxis 150mg (Due to risk of pregnancy-induced HTN)
- Monitor fetal growth closely
- Detailed fetal anomaly scan at 20-22 weeks as per normal pregnancies
- Serial growth scans at 28 weeks
Glycemic targets in GDM
7 point blood sugar profile
- Before and after meals x3
+ before sleeping
*at least 2 days a week, consecutive
Targets:
Pre-meal (5mins before): 4.4 – 5.5 mmol/L
Post meal (2h from start of food intake): 5.5 – 6.6 mmol/L
Bedtime: 4.4 – 5.5 mmol/L (min 3h from dinner time)
Serial growth scan at 28 weeks to assess for
- Abdominal circumference (AC)
- Head circumference (HC)
- H/A ratio
- Liquor volume
- Estimate fetal weight
Management of pre-existing DM in pregnancy
- MDT Mx
- Diabetic nurse, Dietician, Obstetrician, Endocrinologist - Assess for complications of DM
- Referral to ophthalmologist TRO diabetic retinopathy
- Check kidney function (UECr), consider referral to nephrologist if needed - 5mg folic acid p
- reduce congenital abnormalities - HbA1c target 6.0-6.5%
- reduce congenital abnormalities - Monitor blood sugar profile more regularly
- 7 point blood sugar profile
- Before and after meals x3
+ before sleeping
(at least 2 days a week, consecutive) - Early FA scan at 17-18 weeks and repeat at 20 weeks
- If T1DM, test for ketonuria if unwell or hyperglycemic
- Switch OHGA to insulin but metformin can continue
- insulin regime - Aspirin 150mg od (Due to risk of pregnancy-induced HTN)
- Monitor fetal growth closely
- EARLY fetal anomaly scan (17-18 weeks)
- Detailed fetal anomaly scan at 20-22 weeks as per normal pregnancies
- Serial growth scans after 28 weeks - Monitor for maternal Cx (Renal, cardio, eye)
Antenatal management - Insulin regime for pre-existing DM pregnancy
Combination of short/ intermediate acting insulin
- Up to 4 injections daily (pre-meal + bedtime)
- High sugar readings BEFORE meals: Intermediate acting insulin
- High sugar readings AFTER meals: Short-acting insulin prior to each meal to cover sharp rise due to meals
*Insulin does not cross placenta
Timing of delivery for pregnant woman with DM
- Good diet control: Deliver by 40 weeks + 6 days
- Good control with insulin: Delivery at 38 weeks
- Poor control with diet towards end of pregnancy: Delivery at 38 weeks
- Poor control with insulin: Aim as close at 37 weeks
Intrapartum care for mom and fetus
- Tight glucose control in labour ~4-7 mmol/L
- Dextrose drip with separate insulin infusion adjusted according to sliding scale with hourly assessment of blood glucose level to guide titration
- <4mmol/L –> Stop insulin infusion
- 4-7mmol/L –> Continue 1u/h
- >7mmol/L –> Increase to 2u/h - Aim vaginal delivery
- Continuous CTG monitoring
Postpartum for GDM
- Encourage breastfeeding (improves glucose metabolism in the short-term)
- If on insulin, usually can go off insulin immediately
- Monitor sugars and check with 2-point 75g OGTT 6 weeks after delivery
-> Normal: Repeat every 1-3 years
-> Abnormal: Refer to specialist - Contraception counselling
*Estrogen-containing contraceptives not recommended for women with DM + vascular disease
Postpartum for pre-existing DM
- Encourage breastfeeding (improves glucose metabolism in the short-term)
- Use pre-pregnancy insulin regime if previously on insulin
- Consider reducing dose if breastfeeding due to risk of hypoglycemia
- If on OHGA pre-preg, then continue low dose insulin or metformin
- For next pregnancy, book early: Do 2 point OGTT in first trimester
- Contraception counselling
*Estrogen-containing contraceptives not recommended for women with DM + vascular disease
Normal 3-point OGTT
Fasting: 3.0-5.0 mmol/L
1h </= 9.9
2h </= 8.4
How to prepare woman with pre-existing DM for future pregnancy?
Multidisciplinary team
Sugar control
- diet, exercise, control bmi
- HbA1c aim below 6
Screen for macro and micro xm
- Retinopathy, nephropathy, neuropathy
- HTN
If HTN, change ace inhibitors
Contraception if HbA1c high to prevent pregnancy
Folic acid in case of pregnancy
Subsequent risk of development of DM in GDM patients
- Approximately 60% of women with a past history of GDM develop T2DM later in life
- Each additional pregnancy also confers a threefold increase in the risk of T2DM in women with a history of GDM
