Thyroid Nodules In Pregnancy


Findings presented at the Ninth Annual Meeting and Clinical Congress of the American Academy of Clinical Endocrinologists suggest that thyroid nodules in pregnant patients may be more likely to be malignant.

Dr. Henry B. Burch of Walter Reed Army Medical Center, Washington, DC, reviewed published experimental studies and found that it is possible that the immunological changes in pregnancy may promote nodule formation. Additional analysis led Dr. Burch to conclude that thyroid nodules in pregnant women are more likely to be malignant (cancerous). His summary of 4 studies showed that of a total of 186 pregnant patients with thyroid nodules, the overall surgically proven thryoid cancer rate was 27%.

Dr. Burch suggests several causes. It may be that previously occult (hidden) thyroid cancer grows more rapidly during pregnancy. Or, the thyroid might be stimulated by the increase of TSH during pregnancy or the presence of human chorianic gonadotropin (a hormone produced by the placenta). Other considerations might include the slight immunosuppressed (decreased effectiveness of the immune system) state of pregnancy or relative iodine deficiency.

About 11,000 new cases of thyroid cancer are identified each year. Approximately 10% of the population will develop thyroid nodules (lumps) of those about 5% are malignant. Women are 3 times more likely than men to develop thyroid cancer.

Thyroid cancer is one of the most curable. Treatment consists of removal of the affected lobe and all or part of the unaffected lobe. This may be followed with radioactive active iodine therapy. Those treated will require thyroid hormone replacement.

Diagnostic studies or treatment with radioactive iodine should be avoided during pregnancy. Dr. Burch recommends fine needle biopsy as the diagnostic tool of choice during pregnancy. He recommends that if a thyroidectomy is necessary that it be delayed until at least the second trimester of pregnancy or shortly after delivery.