How should thyroid function be managed in a pregnant patient with hypothyroidism on levothyroxine?

How should thyroid function be managed in a pregnant patient with hypothyroidism on levothyroxine?

• A. Increase the levothyroxine dose as needed based on TSH/free T4; monitor thyroid function throughout pregnancy
• B. Stop levothyroxine during pregnancy
• C. Do not monitor thyroid function during pregnancy
• D. Switch to a different medication

Answer: (A)

In pregnancy, the body's need for thyroid hormone rises due to hormonal changes and fetal needs, so someone with hypothyroidism on levothyroxine usually requires a higher dose to stay within the normal thyroid range. The best approach is to increase the levothyroxine dose as needed and monitor thyroid function throughout pregnancy. This means checking TSH and free T4 regularly—often every 4 weeks in early pregnancy—and adjusting the dose up or down to keep TSH in the trimester-specific target range and free T4 normal. Stopping the medication, avoiding monitoring, or switching to another drug are not appropriate; levothyroxine remains the standard therapy, and maintaining euthyroidism is important for both maternal and fetal health.

In pregnancy, the body's need for thyroid hormone rises due to hormonal changes and fetal needs, so someone with hypothyroidism on levothyroxine usually requires a higher dose to stay within the normal thyroid range. The best approach is to increase the levothyroxine dose as needed and monitor thyroid function throughout pregnancy. This means checking TSH and free T4 regularly—often every 4 weeks in early pregnancy—and adjusting the dose up or down to keep TSH in the trimester-specific target range and free T4 normal. Stopping the medication, avoiding monitoring, or switching to another drug are not appropriate; levothyroxine remains the standard therapy, and maintaining euthyroidism is important for both maternal and fetal health.