Perinatologist Corner - C.E.U/C.M.E. Modules
Thyroid Disorders in Pregnancy
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9. Postpartum management of women with thyroid disorders
Postpartum Thyroiditis
Postpartum thyroiditis
occurs in women within one year after parturition. It usually presents in one of three ways: Transient hyperthyroidism alone Transient hypothyroidism alone Transient hyperthyroidism followed by hypothyroidism and then recovery. Postpartum thyroiditis can also occur after spontaneous or induced abortion. The presentation may be identical to subacute lymphocytic (painless) thyroiditis, but the course may be more variable. See hyperthyroidism below.
Hyperthyroidism
Women who have been diagnosed with true Graves’ disease
during pregnancy will need definitive therapy. They may continue on thioamide therapy indefinitely with appropriate follow up, but it is usually logistically easier to ablate the gland. This may be accomplished surgically, but the complications (inadvertent hypoparathyroidism, recurrent laryngeal nerve damage, etc.), while uncommon, make radioactive iodine therapy a more attractive option. Referral to an endocrinologist for dosage calculation and administration of the I-131 is usually necessary. It is recommended that patients should not conceive, or breast feed, for at least 6 months after treatment. The radioisotope may be taken up by the fetal thyroid as early as at 10 weeks gestation and result in permanent ablation of the fetal gland, so reliable contraception is a must. Mothers who want to breast feed may want to continue thioamides until their baby is weaned. Following radioactive ablation of the thyroid, about 80% of patients will develop hypothyroidism and require thyroxine replacement therapy, so careful follow up remains important.
Hypothyroidism
Women who have been diagnosed with hypothyroidism
may require an adjustment of their thyroxine dose postpartum as well. If the patient develops the common postpartum symptoms of depression, fatigue, excess weight gain, and irregular menses, it is certainly appropriate to look for hypothyroidism. Subclinical thyroiditis is more common in the puerperium, and will commonly result in hypothyroidism. An elevated TSH will usually be enough evidence to diagnose hypothyroidism, and appropriate treatment with thyroxine replacement can be begun.
Thyroid Nodule
If a thyroid nodule has been detected during pregnancy and fine needle aspiration has returned with negative cytology, a follow up exam is in order at the postpartum visit. A repeat scan, FNA, and referral should be ordered as indicated.