The influence of selenium supplementation on postpartum thyroid status in pregnant women with thyroid peroxidase autoantibodies

Context: Pregnant women who are positive for thyroid peroxidase antibodies [TPOAb(+)] are prone to develop postpartum thyroid dysfunction (PPTD) and permanent hypothyroidism. Selenium (Se) decreases thyroid inflammatory activity in patients with autoimmune thyroiditis. Objective: We examined whether Se supplementation, during and after pregnancy, influences the thyroidal autoimmune pattern and function. Design: This was a prospective, randomized, placebo-controlled study. Setting: The study was conducted in the Department of Obstetrics and Gynecology and Department of Endocrinology. Patients: A total of 2143 euthyroid pregnant women participated in the study; 7.9% were TPOAb(+). Interventions: During pregnancy and the postpartum period, 77 TPOAb(+) women received selenomethionine 200 mu g/d (group S1), 74 TPOAb(+) women received placebo (group S0), and 81 TPOAb(-) age-matched women were the control group (group C). Main Outcome Measures: We measured the prevalence of PPTD and hypothyroidism. Results: PPTD and permanent hypothyroidism were significantly lower in group S1 compared with S0 (28.6 vs. 48.6%, P < 0.01; and 11.7 vs. 20.3%, P < 0.01). Conclusion: Se supplementation during pregnancy and in the postpartum period reduced thyroid inflammatory activity and the incidence of hypothyroidism.