Postpartum Thyroiditis

Described as a transient thyroid disorder, postpartum thyroiditis (PPT) affects 5 percent to 9 percent of women within 12 months after giving birth. PPT patients may experience hypothyroidism, hyperthyroidism or hyperthyroidism followed by hypothyroidism within this time period. While most PPT patients regain normal thyroid function, as many as 25 percent to 30 percent of PPT patients develop permanent hypothyroidism.

During pregnancy, a woman’s immune system is suppressed. Following birth of the child, the immune system experiences a rebound of activity. In PPT cases, while the exact cause is unknown, some believe that the immune system overcompensates during this surge of activity and develops antibodies against its own thyroid tissues.

PPT patients will present abnormal levels of thyroid hormones and TSH as seen for hypo- and/or hyperthyroidism. Studies have shown that nearly all PPT patients also test positive for autoantibodies to thyroid peroxidase (TPOAb). The presence of TPOAb in the first trimester of pregnancy is correlated to higher incidence of miscarriage and demonstrates predictive value for women who will go on to develop PPT following delivery. 30 percent to 50 percent, or more, of women who are TPOAb positive in the first trimester of pregnancy go on to develop PPT.

Hypothyroidism seen in PPT can be managed with proper dosage of synthetic thyroid hormone.

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For More Information

• American Thyroid Association
• Thyroid Foundation of Canada
• National Graves' Disease Foundation
• Gland Central
• American Association of Clinical Chemistry (Clinical Chemistry Journal)
• The Endocrine Society
• CLIANet (Clinical Laboratory Improvement Amendments)
• NCCLS (National Committee for Clinical Laboratory Standards)