Thyroid Disease in Pregnancy

Question 1

Why do you have to be careful about hyperthyroid presentation in pregnancy?

Answer 1

Generally, have a low threshold for checking thyroid function in pregnancy but be wary as normal pregnancy usually mimics hyperthyroidism.

Question 2

If hyperthyroid disease is present in pregnancy what is the usual cause?

Answer 2

Usually Grave’s disease. Normally severity decreases during pregnancy but transient exacerbations can occur especially in the 1st trimester and post-partum.

Question 3

What are the complications of hyperthyroid disease in pregnancy?

Answer 3

Prematurity
Foetal loss
Malformations
TSH receptor stimulating antibodies can increase in pregnancy resulting in foetal thyrotoxicosis after 24 weeks causing prematurity. If mother on antithyroid drug this may mask the signs in foetus until it has metabolised it all a few days later so monitor TFTs closely.

Question 4

How should hyperthyroid disease be managed during pregnancy?

Answer 4

Carbimazole fine
PTU – propylthiouracil (crosses placenta less and used in new diagnosis) also preferred post-partum due to low milk concentrations.

Question 5

What are the complications of hypothyroid disease in pregnancy?

Answer 5

Infertility
Miscarriage
Stillbirth
Anaemia
PET
IUGR
Reduced IQ and neurodevelopmental delay

Question 6

How is hypothyroid disease in pregnancy managed?

Answer 6

Optimise T4 preconception
Monitor T4 and TSH each trimester or 6 weeks post dose adjustment
Use pre pregnancy levothyroxine doses postpartum