Thyroid disease in pregnancy

Question 1

Why can some people develop thyroid in pregnancy and why can existing thyroid disease get worse?

Answer 1

Because of an increased demand on the thyroid to maintain homeostasis

Question 2

What happens to the thyroid gland during pregnancy?

Answer 2

Increases in size and produces more T4

Question 3

What do you need to do if the patient is already on thyroxine when they become pregnant?

Answer 3

Increase dose by 25mg day asap

Then increase as needed

Question 4

What TSH levels should you aim for in pregnancy?

Answer 4

TSH <3mU/l

Question 5

What are some of the risks of hypothyroidism during pregnancy?

Answer 5

Abortion
Haemorrhage
Premature birth
Neuronal defects and slowed mental functions

Question 6

Why can hCG be a problem in pregnancy?

Answer 6

hCG can mimic TSH thus producing more T4 and less TSH therefore mimicking hyperthyroidism.

Question 7

How do you distinguish between high hCG and hyperthyroidism?

Answer 7

TRAb positive in hyperthyroidism and resolves on birth

Question 8

What are some of the complications of hyperthyroidism in pregnancy?

Answer 8

Infertility
Miscarriages
Thyroid crisis in labour
Transient neonatal thyrotoxicosis

Question 9

How do you treat hyperthyroidism that develops during pregnancy?

Answer 9

Wait and see if it resolves- remember hCG
If not:
Beta-blockers if needed
Low does antithyroid drugs

Question 10

What antithyroid drugs should be used during pregnancy?

Answer 10

1st trimester- PTU

2nd/3rd trimester- Carbimazole