Acrobat
MS WordPerinatologist Corner - C.E.U/C.M.E. Modules
Thyroid Disorders in Pregnancy
Sponsored by The Indian Health Service Clinical Support Center
7. Thyroiditis
The majority of new cases of hypothyroidism diagnosed during pregnancy are a result of Hashimoto’s disease
(chronic autoimmune thyroiditis). This disorder may present as an enlarged thyroid, but usually is not associated with tenderness of the gland.
Subacute lymphocytic thyroiditis is usually characterized by a tender and enlarged gland. In this disorder there may be an initial transient hyperthyroid phase as the gland is destroyed and thyroid hormone is released into the circulation, but in most patients hypothyroidism will eventually result. If the patient is seen in the hyperthyroid phase, diagnostic confusion with Graves’ disease may occur. Women with thyroiditis will have elevated levels of anti-thyroid peroxidase antibodies and thyroid antimicrosomal antibodies in over 90% of the cases. The higher the titer of autoantibodies, the more likely it is that permanent hypothyroidism will result. They will not have thyroid stimulating antibodies (TSI) as patients with Graves’ disease commonly do, and this may be helpful in making the differential diagnosis before the full clinical picture evolves.
While measuring levels of thyroid autoantibodies is usually not necessary to establish a diagnosis of thyroid disease, this is an area where obtaining them may be useful. The other major cause of hypothyroidism is prior or current treatment of maternal Graves’ disease (prior thyroidectomy or radioactive iodine treatment, or current thioamide therapy) as discussed above.
Women from developing countries commonly suffer from iodine deficiency, which is the most frequent cause of hypothyroidism worldwide. It is almost always associated with a goiter. If untreated, it will result in congenital cretinism manifested by growth restriction, microcephaly, and generalized neurologic deficit.
