Thyroid Disease in Pregnancy

Question 1

What is the physiology of thyroid related hormones in pregnancy?

Answer 1

• 1^st trimester = fall in TSH and rise in free T4 is expected
• Free T4 then falls with advancing gestation

Question 2

What thyroid related things are screened for in booking?

Answer 2

• Current thyroid disease
• Previous thyroid disease
• 1^st degree FHx thyroid disease
• AI conditions - Coeliac’s, T1/T2DM, GDM etc

Question 3

What is the management of hypothyroidism pre-conception and throughout pregnancy?

Answer 3

• Beginning of pregnancy = thyroxine increased by 25 μg - even if currently euthyroid
  
  • Repeat TFTs in 2 weeks and perform in each trimester to adjust dose if required
• Corrected hypothyroidism has no influence on pregnancy outcome or complications
  
  • Suboptimal replacement is associated with developmental delay and pregnancy loss

Question 4

What are the diagnostic criteria for postpartum thyroiditis?

Answer 4

1. Patient is ≤12 months after giving birth
2. Clinical manifestations are suggestive of hypothyroidism
3. TFTs alone - no need to measure TPO antibodies (TPO antibodies are present in 90%)

Question 5

What are the 3 stages of postpartum thyroiditis?

Answer 5

1. Thyrotoxicosis
2. Hypothyroidism
3. Euthyroid

Question 6

What is the management of postpartum thyroiditis?

Answer 6

• Thyrotoxic phase - propranolol (anti-thyroid drugs are not used)
• Hypothyroid phase - thyroxine
• TFTs measured every 2 months after the thyrotoxic phase

Question 7

What is the management of hyperthyroidism in pregnancy?

Answer 7

• Treat medically/No surgery
• Give lowest acceptable dose:
  
  • Propylthiouracil (1^st trimester)
  • Carbimazole (2^nd and 3^rd trimester)
• Radioactive iodine in contraindicated - obliterates foetal thyroid

Question 8

What are the side effects of the management of hyperthyroidism in pregnancy?

Answer 8

• Foetal hypothyroidism – hence lowest possible dose
  
  • 33% of women can actually stop treatment during pregnancy
  • Doses usually require readjustment postpartum to prevent relapse
• Agranulocytosis

Question 9

What are the complications of uncontrolled thyrotoxicosis?

Answer 9

• Miscarriage
• PTL
• IUGR
• TSH-receptor stimulating antibodies can cross the placenta → babies born to +ve mothers should be reviewed by the neonatology team

Question 10

What is the management of hyperparathyroidism in pregnancy?

Answer 10

• Mild to Moderate = Adequate hydration and low calcium diet
• Severe = Parathyroidectomy

Question 11

What are the complications hyperparathyroidism in pregnancy?

Answer 11

• Miscarriage
• Intrauterine death
• Preterm labour
• Neonatal tetany

Question 12

What is the management of hypoparathyroidism in pregnancy?

Answer 12

• Vitamin D
• Oral calcium supplements
• Regular monitoring of calcium and albumin

Question 13

What are the complications of hypoparathyroidism in pregnancy?

Answer 13

• 2^nd trimester miscarriage
• Foetal hypocalcaemia
• Neonatal rickets