Thyroid disease

Question 1

Hypothryoidism

Answer 1

Untreated disease rare but associated with high preinatal mortality
Subclinical hypothyroidism: miscarriage, preterm delivery and intellectual impairement in childhood
Slight increased risk of pre-eclampsia
Monitor TSH six-weekly and replace with thyroxine

Question 2

Hyperthyroidism

Answer 2

Untreated disease rare
Inadequately treated disease increases perinatal mortality
Antithyroid Ab may cross placenta and cause neonatal thyrotoxicosis and goitre
‘Thyroid storm’ near or at delivery: acute symptoms and heart failure
Treated with propylthiouracil (NOT carbimazole). This can cross placenta and cause neonatal hypothyroidism, lowest dose used
Thyroid function texted monthly
Graves often worsens after delivery

Question 3

Postnatal thyroiditis

Answer 3

Common (5-10%)
Can cause postnatal depression
Risk factors include antithyroid antibodies and TIDM
Transient and usually subclinical hyperthyroidism 3 months postpartum, followed by about 4 months of hypothyroidism. This is permanent in 20%