Thyroid Disease in Pregnancy

Question 1

What physiological change occurs with thyroid hormones during pregnancy?

Answer 1

increase in levels of thyroxine-binding globulin (TBG). This causes an increase in the levels of total thyroxine but does not affect the free thyroxine level.

Question 2

What are the indication to screen for thyroid disease at booking?

Answer 2

• Current thyroid disease
• Previous thyroid disease
• 1st degree Fhx thyroid disease
• other autoimmune condition

Question 3

How much monitoring is done for a hypothyroid patient?

Answer 3

TFTs checked every 2-4 wees

Goal is to keep TSH <4mmol/L

Question 4

What is the target for TSH in a hypothyroid patient?

Answer 4

<4mmol/L

Question 5

How to manage hypothyroidism medically during pregnancy?

Answer 5

continue levothyroxine. Adjust dose according to TFTs. Often require higher dose by up to 50%, esp. during first trimester.

Increase the dose of levothyroxine by 25–50 μg (EVEN IF CURRENTLY EUTHYROID) and referral to an endocrinologist at diagnosis of pregnancy.

Question 6

How to monitor TFTs postnatally?

Answer 6

6-8 weeks postnatal check with GP.

Question 7

How to medically manage postpartum thyroiditis?

Answer 7

Thyrotoxic phase = propanolol

Hypothyroid phase = levothyroxine

Question 8

How to medically manage hyperthyroidism during pregnancy?

Answer 8

1st trimester = propylthiouracil

Rest of pregnancy = carbimazole

Question 9

What are the s/e of carbimazole?

Answer 9

Agranulocytosis