Postpartum thyroiditis is a painless condition. Most of the patients with postpartum thyroiditis are symptom-free or showing mild symptoms during thyrotoxic state, including irritability, palpitation, fatigue, and heat intolerance. The hypothyroid state of postpartum thyroiditis is mostly symptomatic, including constipation, dry skin, fatigue, impaired concentration, cold intolerance, and paresthesia. A study reported that patients with postpartum thyroiditis and positive TPO antibodies were more symptomatic than patients who had negative TPO antibodies.[8]

The diagnosis of postpartum thyroiditis depends on clinical presentation and thyroid function tests (level of TSH and free T4). Patients with postpartum thyroiditis have similar biochemical findings that can be detected in the patients with painless thyroiditis: high or upper limit of normal serum free T4 and T3 levels and low serum TSH level in the hyperthyroid phase, which could be subclinical or overt. In patients with hyperthyroid state followed by hypothyroid state, serum T4 level could be low for days to weeks before serum TSH level rises beyond the normal range, as a result of prolonged suppressed TSH which had occurred in the hyperthyroid state. Serum levels of anti-thyroid peroxidase antibody are high in 60 to 85 percent of patients with postpartum thyroiditis and are highest in the hypothyroid state or soon thereafter. Some of the patients may have a slight increase in C-reactive protein and/or erythrocyte sedimentation rate.[9][10][11] Clinicians in charge of women after pregnancy have to be aware of the possible postpartum thyroid dysfunction, which can result in different symptoms during the postpartum period.

A prospective study that evaluated 605 asymptomatic pregnant women and women in the postpartum period showed that none of the cases with thyrotoxicosis and 40% of cases with hypothyroid state needed treatment. If treatment is necessitated, it could usually be tapered over one year. Several studies have shown that long-term treatment would be required in up to 20% of cases with postpartum thyroiditis. There have not been any prospective studies to evaluate when and how to treat postpartum thyroiditis. Management of the thyrotoxic state is guided by its transitory nature. Anti-thyroid medications (methimazole and propylthiouracil) have been ineffective in the treatment of the thyrotoxic state of postpartum thyroiditis as it is destructive thyroiditis in which there is no increase in the synthesis of thyroid hormones. Symptoms are usually mild. In a few cases with clinically significant symptoms, a low dose of propranolol may be helpful. The thyrotoxic state of postpartum thyroiditis should be differentiated from Graves disease. When thyrotoxic state of postpartum thyroiditis resolved, the serum TSH level should be measured in about four to eight weeks (or in case of development of new symptoms) in order to screen for the hypothyroid state. In cases who develop significant symptoms, and currently lactating or cases who want to get pregnant, treatment should be initiated. Treatment with levothyroxine (LT4) 4 should be considered in the hypothyroid state of postpartum thyroiditis if the patient has mild symptoms, or advice if the patient wants to get pregnant again. If treatment is delayed, thyroid function must be evaluated every four to eight weeks until the patient gets euthyroid. In addition, women must be counseled to have contraception. The duration that the patient should continue to take LT4 has not been evaluated. Based on the guidelines, the euthyroid state should be maintained in cases who are pregnant or wants to get pregnant. To assess if the hypothyroid state of postpartum thyroiditis is permanent or transient, LT4 doses can be tapered starting 12 months after delivery. The dose should be tapered gradually, and serum TSH level must be monitored every six to eight weeks.[8]

• Graves disease
• Hashimoto thyroiditis 
• Postpartum mood disorder 

As discussed above the clinical course of postpartum thyroiditis is variable. Only 30% of cases with postpartum thyroiditis will remain in hypothyroid state one year postpartum.[12]

Thyroid function in most of the cases with postpartum thyroiditis returns to a normal state within 12 to 18 months of the onset of the symptoms. However, some cases do not recover from the hypothyroid phase, and they will develop permanent hypothyroidism.

Endocrinology should be consulted if there is any question as to the diagnosis or other issues.

Postpartum thyroiditis is not a preventable disease. Patients, especially those who are high risk for developing postpartum thyroiditis (as discussed above), should counsel with the primary care physician or obstetrician if they have symptoms and do not assume that the symptoms are related to the stress of caring for a newborn.

All clinicians should be aware of postpartum thyroiditis as it is common, and symptoms usually do not develop at the six-week postpartum visit. Screening of high-risk women for developing postpartum thyroiditis such as a positive test for antithyroid peroxidase antibody, history of postpartum thyroiditis, type 1 diabetes mellitus is recommended by Endocrine Society clinical guidelines. High-risk women should be evaluated for serum TSH levels at three and six months postpartum. [1] If TSH level is not normal, TFTs should be repeated in one to two weeks (check T3 level if TSH is low). Postpartum thyroiditis screening for all pregnant women is not recommended, as there is not enough evidence to support this.