Assessment of serum thyroid hormone autoantibodies in the first trimester of gestation as predictors of postpartum thyroiditis

Salvatore Benvenga; Roberto Vita; Flavia Di Bari; Carmela Lo Re; Angela Scilipoti; Grazia Giorgianni; Loredana Grasso; Marina Raffaella Galletti; Mattia Grazia Mandolfino; Maria Le Donne

doi:10.1016/j.jcte.2019.100201

Assessment of serum thyroid hormone autoantibodies in the first trimester of gestation as predictors of postpartum thyroiditis

J Clin Transl Endocrinol. 2019 Jul 24:18:100201. doi: 10.1016/j.jcte.2019.100201. eCollection 2019 Dec.

Authors

Affiliations

¹ Department of Clinical and Experimental Medicine, University of Messina, Italy.
² Master Program on Childhood, Adolescent and Women's Endocrine Health, University of Messina, Italy.
³ Interdepartmental Program on Molecular & Clinical Endocrinology, and Women's Endocrine Health, University Hospital, A.O.U. Policlinico G. Martino, 98125 Messina, Italy.
⁴ Division of Obstetrics and Gynecology, University Hospital G. Martino, 98125 Messina, Italy.
⁵ Service of Immunometry and Laboratory Diagnosis, University Hospital G. Martino, 98125 Messina, Italy.
⁶ Department of Human Pathology Gaetano Barresi, University of Messina, Italy.

Abstract

Background: Measurement of serum thyroperoxidase autoantibodies (TPOAb) during gestation as a classical marker for the risk of postpartum thyroiditis (PPT) predicts PPT in 1/3 to 1/2 of women. Very few studies have measured serum thyroid hormone Ab (THAb) during gestation, and none as a possible marker for PPT.

Methods: In 412 women who were followed up from 7 to 11 weeks of gestation through 12 months after delivery, we measured THAb (T3.IgM, T3.IgG, T4.IgM, T4.IgG), thyroglobulin autoantibodies (TgAb) and TPOAb at study entry (7-11 week of gestation).

Results: Sixty-three women (15.3%) developed PPT, which progressed to permanent hypothyroidism (PH) in 34/63 (54%). THAb+ve were 21/412 women (5.1%), the frequency being greater in those who then developed PPT (12/63 [19.0%] vs. 9/349 [2.6%], P = 4.6 × 10^-8), and in the PH subgroup (26.5% [9/34] vs. 10.3% [10/29], P = 0.12). THAb positivity occurred in 9/76 women (11.8%) who were TgAb and/or TPOAb+ve compared to 12/336 women who were TgAb and TPOAb negative (3.6%, P = 0.0031). Of these 9 THAb+ve, TgAb and/or TPOAb+ve women, all (100%) developed PPT compared to 3/11 (27.3%, P = 0.0011) THAb+ve, TgAb and/or TPOAb negative women. Of these 9 and 3 PPT women, 8 and 1 progressed to PH (88.9% and 33.3%, respectively, P = 0.12).

Conclusions: Gestational positivity of THAb enhance enormously the predictivity for PPT of gestational positivity of TPOAb/TgAb. However, their low frequency (5.1%) and their sensitivity (17.5% [21/63]) go against their application in lieu of TPOAb/TgAb.

Keywords: DM-1, type 1 diabetes mellitus; FNAB, fine-needle aspiration biopsy; FT3, free triiodothyronine; FT4, free thyroxine; GD, Graves’ disease; HT, Hashimoto’s thyroiditis; L-T4, Levothyroxine; PH, permanent hypothyroidism; PPT, Postpartum thyroiditis; Postpartum; Postpartum thyroiditis; Pregnancy; THAb, thyroid hormone autoantibodies; TPOAb, thyroperoxidase autoantibodies; TSH, thyrotropin; Tg, thyroglobulin; TgAb, thyroglobulin autoantibodies; Thyroid autoimmunity; Thyroid hormone autoantibodies; US, ultrasound; UST, ultrasonography signs suggestive of thyroiditis.