The Guidelines also recommend ultrasound to determine the features of the nodule, and monitor growth. If a nodule is less than 10mm in size, a fine-needle aspiration (FNA) biopsy of the thyroid is not required unless there are suspicious characteristics.
If a nodule is growing, or if there is persistent cough or vocal problems, or any other suspicious indicators from the history, the Guidelines recommend an FNA be performed. FNA is considered safe during pregnancy.
When cancerous thyroid nodules are discovered during the first or second trimester, surgery should be offered in the second trimester. Well-differentiated thyroid cancers grow slowly, so if the evaluation indicates that the cancer is papillary or follicular, and there is no evidence of advanced disease, a woman may be offered the opportunity to wait until after childbirth for surgery.
A pregnant woman who has previously had thyroid cancer or a woman who has a confirmed thyroid cancer who is waiting until after delivery for thyroid surgery can receive treatment that will allow TSH to remain suppressed but detectable. Ideally, the free T4 or total T4 levels should remain within the normal range for pregnancy.
Radioactive iodine should not be given to women who are pregnant or breastfeeding.
Women who receive therapeutic doses of radioactive iodine should wait six months to a year to become pregnant, to ensure that thyroid function is stable, and the thyroid cancer is in remission.
Learn more about Thyroid Nodules and Thyroid Cancer in Pregnancy.