Postpartum Mood Disorders and Thyroid Autoimmunity

Because of the rapid emotional and endocrine changes in the postpartum period (1), postpartum mood disorders represent the most frequent form of maternal psychiatric morbidity (2-4).Postpartum mood disorders vary from a mild form of transient depression (maternity blues) to fullblown postpartum depression and severe psychosis (5,6).Postpartum depression affects 10-30% of women within 1 year after delivery (7), and its risk is measurable already at 3 (8) or 7 days (2) postpartum.This risk predicts depression development in the following months (9, 10).Thyroid function abnormalities exhibit comorbidity with various psychiatric disorders, including maternal depression.There are one-tenth of a million studies on mood disorders, but fewer than 5,000 (3.9% of almost 125,000) concern mood disorders in the postpartum period.Similarly, studies on autoimmune thyroid disease are almost 20,000, but only 72 (3.7% of 19,360) concern postpartum mood disorders and thyroid disorders, and merely 5 focus on postpartum mood disorders and thyroid autoimmunity.Thus, we hope that our opinion will stimulate interest. pOSTpARTUM AFFECTiVE DiSORDERS AnD THYROiD DYSFUnCTiOnAffective disorders and autoimmune thyroiditis are well known to affect women during puerperium.Up to 23% of all new mothers experiences thyroid dysfunction postpartum (11), compared with a prevalence of 3-4% in the general population (12).Maternal thyroid autoimmunity refers to the detection of thyroid autoantibodies against thyroperoxidase (TPOAb) and/or thyroglobulin (TgAb) in combination with normal thyroid function, and it has been reported to affect between 8 and 14% women in reproductive age (13).Concerning positivity for TPOAb, approximately 10% of pregnant women are TPOAb positive, and around one-third to half of them will develop postpartum thyroiditis (PPT) within 12 months after delivery (11,14).At least 2-3% of women have some form of thyroid dysfunction during pregnancy, and 10-17% of women have thyroid autoimmune disease despite euthyroidism (15,16).Thyroid dysfunction in pregnancy is classified as (i) primary overt hypothyroidism (elevated TSH and a decreased FT4 during gestation with both concentrations outside the trimester-specific reference ranges) or subclinical hypothyroidism (with a TSH elevated beyond the upper limit of the pregnancy-specific reference range); (ii) hyperthyroidism (autoimmune Graves' disease or gestational transient thyrotoxicosis) (17); and (iii) positivity of thyroid autoantibodies, which increases the risk of thyroid dysfunction