Download Gestational Diabetes

Gestational Diabetes (Lin)
Epidemiol
ogy
Risk
factors
Definition
(WHO)
Pathophy
siology
3-8% of all pregnancies in Australia
 Obesity (BMI >30)
 FHx of diabetes
 Previous baby >4.1 kg
 Previous unexplained stillbirth
 Previous congenital abnormality
 Chronic HT
 Maternal age > 25 yo
>7.8 mmol/L fasting blood glucose
>11.1 mmol/L 2 hours post 75g oral glucose
 human placental lactogen and cortisol (both are insulin antagonists)   insulin resistance in
mum  mum’s pancreas secretes  insulin to maintain carbohydrate metabolism  fall in blood
glucose levels  following carbohydrate challenge, levels of glucose are higher than in nonpregnant state.
Glucose crosses placenta by facilitated diffusion  fetal blood glucose levels closely follows
maternal level – foetal BSL normally maintained within narrow limits
Glucose crosses placenta by facilitated diffusion
Screening
Mx
Macrosomia arises from fetal hyperglycemia  Hyperinsulinemia (promoting fetal growth)
Polyhydramnios arises from fetal polyuria (Hyperosmolar state)
At 26-28 weeks.
1. Glucose Challenge Test (GCT)
a. Measure plasma glucose ONE hour after either 50 or 75g oral glucose load given in NONFASTING state
b. POSITIVE if ≥7.8 mmol/L (50g) or ≥8.0 mmol/L (75g)
2. Glucose Tolerance Test (GTT)
a. TWO-hour 75g FASTING
b. POSITIVE if fasting glucose level ≥ 5.5 mmol/L or 2hr level ≥8.0 mmol/L
3. After diagnosis of DM and 6-8 weeks post-delivery, repeat 75g OGTT
Team: Obs, diabetes physician, diabetes educator, dietician, midwife, paediatrician
ANTENATAL CARE AND PRECONCEPTION
 Glucose monitoring and control
o Through diet, exercise, self-monitoring diary and +/- insulin
o Target
 Fasting glucose <5mmol/L
 1h post prandial glucose <8mmol/L
 2h post prandial glucose <7mmol/L
FETAL MONITORING
 Assessment of fetal growth (US) at 18-20 weeks
 > 36 weeks: CTG weekly due to ?risk of IUFD
INTRAPARTUM CARE
 Aim: achieve NVD between 38-40 weeks
 >38 weeks: consider IOL
 BSL tested at hourly intervals
 Continuous fetal monitoring and fetal blood sampling if abnormal CTG
 Stop insulin at delivery
POST-PARTUM:
Cx
Prognosis
 Hypoglycaemia in the first 24hrs following delivery – Infant still continue to produce insulin
o Encourage BF straight away or formula feed, monitor baby glucose level, glucose infusion
 Full OGTT 6 weeks post delivery and ensure diabetes has resolved
  risk of miscarriage
  risk of congenital fetal abnormality (cleft palate, NTDs, congenital heart disease and other spinal
anomalies)
 Fetal macrosomia  traumatic birth, shoulder dystocia and possible hypoxic damage
 Stillbirths (10-30% of diabetic pregnancies if poorly controlled)
 Polyhydramnios
Maternal:
 Related to women with pre-existing coronary artery disease
 Nephropathy (temporary worsening)
 Retinopathy (progression)
 Coronary artery disease
  risk of pre-eclampsia 2-4x
  infection
 Severe hyper/hypoglycaemia/DKA
 Thromboembolic disease
Neonatal:
 Hypoglycaemia
o Mx: encourage breastfeed straight away, regular monitoring of BSLs, if necessary, glucose
infusion or formula feed
 Hypocalcaemia
 Magnesium deficiency
 Polycythaemia
 Jaundice (due to hyperbilirubinemia from neonatal polycythaemia)
Most women return to normal at post-natal
30-70% risk of GDM recurrence with future pregnancies, 50% risk of TII DM within 5yrs
PRE-Gestational Diabetes
 Two types
o Insulin-dependent (Type I)
o Non-insulin dependent (Type II)
 Ideally, women with pre-gestational diabetes should have a consultation preconception to plan the
pregnancy, discuss control of blood sugar levels and the care that may be involved.
o Examination of eyes, kidneys and blood pressure
 Management:
o Good glycaemic control
o Usually low level of insulin required in first 12 weeks of pregnancy,  throughout pregnancy
o Monitor 3-4 times daily
o Consider IOL after 40 weeks if no other complications and good glycaemic control
 Cx (see above)
o 3 major ones: congenital malformations, spontaneous abortion, and macrosomia.