Postpartum thyroiditis is a general label referring to silent thyroiditis after delivery, which causes mild hyperthyroidism, and a short-lived Hashimoto’s-type of thyroiditis that causes mild hypothyroidism.
Women with thyroid peroxidase (TPO) antibodies are more likely to experience postpartum thyroiditis. Until quite recently, the mild hypothyroid and mild thyrotoxicosis symptoms were simply attributed to the symptoms of postpartum depression—the notorious postpartum blues—thought to be caused by the dramatic hormonal and emotional changes women experience after pregnancy. But recent studies indicate that just under 20 percent of all pregnant women experience transient thyroid problems and subsequent mild forms of thyrotoxicosis or hypothyroidism.