Graves' disease during the first trimester of pregnancy requires a drug-selection approach that differs from standard antithyroid therapy. The clinical scenario and trimester-specific considerations shape which agent is appropriate and how response is monitored.
This protocol applies to patients with Graves' disease who are in the first trimester of pregnancy. This specific gestational window determines the preferred antithyroid drug choice, because not all agents used outside pregnancy are appropriate during this period.
Propylthiouracil (PTU) is the preferred antithyroid agent during the first trimester of pregnancy. The complete dosing regimen, titration approach, and any additional management steps are specified in the full protocol.
Full regimen details — including dose, frequency, and adjustment strategy — are available in the structured protocol below.
The goal is achievement of biochemical euthyroidism, with normalization of serum free T4 and total or free T3. Response is reassessed at defined intervals after therapy is initiated.
DOI: 10.1016/j.ecl.2021.12.004.
Methimazole (MMI) should be used in patients who choose ATD therapy for GD, except (a) during the first trimester of pregnancy when propylthiouracil (PTU) is preferred, (b) in the management of thyroid storm, and (c) in patients with minor adverse reactions to MMI who refuse radioactive iodine (RAI) therapy or surgery.
MMI can be given once-a-day compared to PTU which has a shorter duration of action and is usually administered as 50–150 mg 3 times daily.
Serum TSH, free T4 and total or free T3 should be obtained initially at 2–4 week intervals after starting ATDs, and the dosage should be adjusted accordingly.
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