Optimization of the follow-up of pregnant women with autoimmune thyroid disease

Objective To determine the risk of hypothyroidism in pregnant women with autoimmune thyroid disease and thyrotropin (TSH) Methods Prospective longitudinal study of pregnant women with no personal history of thyroid disease, and with TSH 4 mIU/l) among pregnant women with positive thyroid autoimmunity and those with negative autoimmunity. Results We included 300 pregnant women with mean baseline TSH 1.3 ± 0.6 mIU/l (9th gestational week). Positive thyroid autoimmunity was detected in 17.7% of women (n = 53) at the first trimester. Between the first and the third trimesters, TPO and anti thyroglobulin antibodies titers decreased 76.8% and 80.7% respectively. Thyroid function during pregnancy was similar among the group with positive autoimmunity and the group with negative autoimmunity, and the development of hypothyroidism was 1.9% (1/53) and 2% (5/247) respectively. Pregnant women in whom TSH increased above 4 mIU/l (n = 6), had higher baseline TSH levels compared to those who maintained TSH ≤ 4 mIU/l during pregnancy (1.8 vs. 1.3 mIU/l; p = 0.047). Conclusion In our population, women with TSH levels