To examine the postpartum thyroid dysfunction (PPTD) and positive thyroid antibodies (Ab+) frequency in the Postpartum Depression (PPD) and to investigate if the PPD patients subgroup with PPTD and/or Ab+ have different characteristics.

Eighty one (N=81) patients with PPD, according with DSM-IV criteria, were included. Thyroid function (Free T3, Free T4,TSH), autoimmune status of the thyroid (Thyroperoxidasa antibodies, Thyroglobulin antibodies) and severity of depression (EPDS and 21-item Hamilton scales), were assessed joint with other several demographics, psycho-social and reproductive variables.

Twenty per cent of the patients with PPD had positive thyroid antibodies and 14% present PPTD. Prior history of early stressors in the PPD patients were significantly related with the presence of Ab+: the presence of childhood maltreatments and/or sexual abuse increased thirteen times the probability of Ab+ (OR: 13,01, 95% CI, 2.01-84.02). Greater number of total stressors were associated with Ab+ (p< 0,030), and Ab+ women showed a higher average of total stressors (2,1) than antibody negative women (1,52). Depressed women with PPTD had positive correlation with previous depressive episodes (p< 0,008).

The depressed postpartum women with dysregulation of pituitary-thyroid axis have more early childhood stressors and previous depressive episode. The implication of the inmunitary system and the HPT axis in the etiopathogenesis of the PPD through the activation of the response in front to stress is discussed.