Diabetes & Pregnancy

Question 1

Glucose physiology in pregnancy

Answer 1

• Pregnancy is a state of increasing insulin resistance
• Fasting glucose decreased and post prandial increased compared to non-pregnant
• Normal women double insulin production from 1st to 3rd trimester
• Glycosuria common (filtered glucose>tubuar resorption capacity) and therefore not reliable tool
• Ketosis also more common in pregnancy

Question 2

Pathophsiology

Answer 2

• The placenta produces produces human placental lactogen which increases production of insulin
• If there is maternal insulin resistance and the pancreatic beta islet cells are unable to produce sufficient insulin the mother may develop gestational diabetes

Question 3

Effects of pre-existing DM

Answer 3

• Higher risk of fetal cardiac defects, NTDs and renal abnormalities

Question 4

Affects on fetus

Answer 4

• Glucose crosses the placenta but insulin does not
• Fetus produces own insulin from 10 weeks
• Important for fetal growth
• Increased maternal glucose = increased fetal glucose leading to increased insulin production resulting in macrosomia
• Risk of unexplained IUD
• Labour and delivery may be complicated by shoulder dystocia

Question 5

Insulin requirements during gestation

Answer 5

1. Static or decrease
2. Increase
3. Increase and may reduce slightly towards term

Question 6

Complications

Answer 6

• Infections (particularly UTI)
• Macrovascular arterial disease
  
  • CAD
  • CVD
  • PVD
• Microvascular disease
  
  • Retinopathy (good control actually worsens retinopathy)
  • Nephropathy
  • Neuropathy
• Hypoglycaemia and loss of awareness
• Operative delivery
• DKA
• Incidence of pre-eclampsia increased
• Polyhydramnios can lead to unstable lie, malpresentation and pre-term labour

Question 7

Risks in pregnancy

Answer 7

• Miscarriage
• Congenital malformation
• Stillbirth
• Neonatal death
• Neonatal hypoglycaemia
• Perinatal death
• Fetal macrosomia
• Birth trauma
• Induction of labour or caesarean section
• Transient neonatal morbidity
• Obesity and/or diabetes in baby’s life

Question 8

Neonatal implications

Answer 8

• Hypoglycaemia
• Hypocalcaemia
• Hyperbilirubinaemia/polycythemia
• Idiopathic RDS
• Delayed lung maturity
• Prematurity
• Predispositin to obesity and diabetes in later life

Question 9

Pre-pregnancy glucose targets

Answer 9

• Fasting plasma glucose of 5-7 mmol/l on waking
• Plasma glucose 4-5mmol/l before meals at other times of day
• Aim to keep HbA1c 48mmol/mol (6.5%)
• Avoid pregnancy if HbA1c >86mmol/mol (10%)

Question 10

Extra care during pregnancy

Answer 10

• Case dependant but generally additional monitoring indicated
• Planned delivery 37+0-38+6 to reduce risk of stillbirht and shoulder dystocia

Question 11

Risk factors for developing gestational diabetes

Answer 11

• BMI >30
• Previous macrosomic baby weighing 4.5kg or more
• Previous gestational diabetes
• FHx of diabetes
• Minority ethnic family origin with high prevalence of diabetes

Question 12

Diagnosis of gestational diabetes

Answer 12

• Fasting plasma glucose 5.6mmol/l or above
• 2-hour plasma glucose 7.8mmol/l or above

Question 13

Risks from gestational diabetes

Answer 13

• 40-60% risk of developing T2DM