Overview

• Pregnancy → 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.
• Screen at Booking → perform TFTs if current thyroid disease, previous thyroid disease, 1st degree FHx thyroid disease, any autoimmune conditions (coeliac, DM, GDM).

Making Diagnosis

Clinical Features

Investigations

Management Plan

• Hypothyroidism

  • Antenatal ⇒

    • Referral to joint obstetric and endocrinology clinic.

    • Monitoring → check TFTs every 2-4 weeks (ensure TSH <4mmol/L).

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

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

      </aside>

  • Postnatal ⇒

    • Monitoring → TFTs monitored at 6-8 weeks postnatal check with GP.
    • Postpartum Thyroiditis:
      • Thyrotoxic Phase → propanolol.
      • Hypothyroid Phase → levothyroxine.
• Hyperthyroidism
  • Antenatal ⇒
    • Monitoring → check TFTs every 2-4 weeks (ensure TSH <4mmol/L).
    • Medical:
      • 1st Trimester → propylthiouracil.
      • Rest of Pregnancy → carbimazole. Sfx of agranulocytosis.
      • Radioactive iodine is contraindicated.
      • Adjust doses throughout pregnancy according to TFTs. Often require lower doses (and 1/3 are able to stop treatment during pregnancy).
  • Postnatal ⇒
    • Monitoring → TFTs monitored at 6-8 weeks postnatal check with GP.

Complications →

Prognosis →