RESUMO
BACKGROUND: Thyroid physiology and autoimmunity are altered in pregnancy. While oestradiol, cortisol, and TGF-ß1 are implicated in these phenomena outside pregnancy, their associations with thyroid autoantibodies during pregnancy and postpartum are not thoroughly examined. This study aimed to unravel their eventual associations during pregnancy and postpartum in the same cohort of 93 pregnant women studied prospectively from 2015 to 2017. METHODS: Blood samples were drawn at the 24th and the 36th gestational week and at the 1st postpartum week for measurements of thyroid hormones, TSH, anti-TPO, anti-Tg, oestradiol, cortisol, and TGF-ß1. RESULTS: Serum anti-TPO was greater (P < 0.05) at the 1st postpartum than at the 24th and 36th gestational weeks. At the 36th gestational week, cortisol was greater (P < 0.05) and TGF-ß1 lower (P < 0.05) than at the 24th gestational and the 1st postpartum weeks. At the 1st postpartum week, cortisol correlated negatively with anti-Tg (r = -0.419) (P < 0.05). ΔTGF-ß1 was the best negative and Δoestradiol the best positive predictor of the 1st postpartum week anti-TPO (P < 0.05, b = -0.509; P < 0.05, b = 0.459 respectively). CONCLUSIONS: At postpartum, increased TGF-ß1 is related to a less pronounced anti-TPO increase as compared to the 3rd trimester, suggesting an immunosuppressive role for TGF-ß1. During pregnancy and postpartum, oestradiol, cortisol, and TGF-ß1 are associated with suppression of thyroid autoantibodies.