Preconception Thyrotropin Levels and Thyroid Function at Early Gestation in Women With Hashimoto Thyroiditis

Abstract

Context Preconception optimization of thyroid function in women with Hashimoto’s thyroiditis (HT) is highly recommended to prevent/reduce the risk of thyroid insufficiency at early gestation. Objectives To evaluate the prevalence of 1st-trimester thyroid insufficiency in HT women with preconception thyrotropin (T0-TSH) values consistently ≤2.5 mIU/L with or without l-T4 treatment; to calculate T0-TSH cut-offs that best preconceptionally identified HT women requiring 1st-trimester l-T4 adjustment/prescription. Methods Serum TSH was obtained at 4-6 week intervals from 260 HT pregnant women (122 on l-T4 [Hypo-HT]; 138 euthyroid without l-T4 [Eu-HT]), prospectively followed from preconception up to pregnancy term. ROC-curves were plotted to identify T0-TSH cut-offs best predicting 1st-trimester TSH levels >2.5 mIU/L (diagnostic criterion [dc]-1) and >4.0 mIU/L (dc-2). Results At 1st-trimester, TSH was >2.5 mIU/L in ∼30% of both Hypo-HT and Eu-HT women, and >4.0 mIU/L in 19.7% Hypo-HT and 10.1% Eu-HT women (p 0.038). The optimal ROC-based T0-TSH cut-offs found were: 1.24 mIU/L/1.74 mIU/L in Hypo-HT, and 1.73 mIU/L/2.07 mIU/L in Eu-HT women, for the dc-1 and -2, respectively. T0-TSH values exceeding the above cut-offs resulted in a significantly increased risk of 1st-trimester thyroid insufficiency (ORs[95%CI)] 15.92[5.06-50.15] and 16.68[5.13-54.24] in Hypo-HT; 16.14[6.47-40.30) and 17.36[4.30-70.08] in Eu-HT women, for the dc-1 and -2, respectively). Conclusions The preconception TSH cut-offs that guaranteed a 1st-trimester TSH < 2.5 mU/L in hypothyroid- and euthyroid-HT women were, respectively, almost 50% (1.24 mU/L) and 30% (1.73 mU/L) lower than this gestational target, and1.74 mU/L and 2.07 mU/L in hypothyroid- and euthyroid-HT women, respectively, for a gestational target of 4.0 mU/L.

Innate Immunity in Autoimmune Thyroid Disease during Pregnancy

“…Increasing evidence emphasizes an elevated risk of adverse gestational and neonatal outcomes induced by subclinical hypothyroidism in women during the early gestational period. Particularly, the risk of pregnancy-specific complications has been increased in TPOAb-positive women having serum TSH levels exceeding 2.5 mIU/L, especially in those with serum TSH levels greater than 4.0 mIU/L [28]. Unfortunately, results of randomized clinical trials revealed that thyroid hormone supplementation is unsuccessful in the prevention of adverse pregnancy outcomes in women with AITD.…”

Response to Association of Triglyceride-Glucose Index with Risk of Large for Gestational Age: A Prospective Cohort Study [Letter]

“… 3 Actually, over 30% of women with hypothyroidism (Hypo-HT) and euthyroidism-HT (Eu-HT) have TSH greater than 2.5 mIU/L in early pregnancy, 19.7% of women with Hypo-HT and 10.1% of women with Eu-HT have TSH higher than 4.0 mIU/L (P < 0.05). 4 To prevent/reduce the risk of thyroid insufficiency inducing adverse pregnancy outcomes such as LGA during early pregnancy, preconception thyroid function optimization for women with Hashimoto thyroiditis (HT) through levothyroxine sodium is strongly suggested by guidelines. 5 Second, there is a lack of evaluation data on serum ferritin levels.…”