CC BY 4.0 · Rev Bras Ginecol Obstet 2022; 44(08): 806-818
DOI: 10.1055/s-0042-1756521
Febrasgo Position Statement

Screening, diagnosis and management of hyperthyroidism in pregnancy

Number 8 – Agosto 2022
1   Faculdade de Ciências Médicas de São José dos Campos, São José dos Campos, SP, Brazil
2   Departamento de Obstetrícia, Escola Paulista de Medicina, São Paulo, SP, Brazil
3   Universidade Federal Paraná, Curitiba, PR, Brazil
4   Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil
5   Policlínicas Municipal, Sorocaba, SP, Brazil
6   Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
7   Universidade de Brasília, Brasília, DF, Brazil
8   Universidade Estadual de Campinas, Campinas, SP, Brazil
› Author Affiliations

Key points

  • The physiological changes of pregnancy that interfere with the production, release and availability of the active form of hormones interfere with the diagnosis and management of hyperthyroidism during pregnancy.

  • Gestational thyrotoxicosis or transient hyperthyroidism, the most common cause of hyperthyroidism in pregnancy, is related to the increased production of human chorionic gonadotropin (hCG) and may persist until week 18.

  • Untreated hyperthyroidism can have fetal, neonatal, and maternal effects.

  • The obstetrician must be aware of the fetal, neonatal and/or maternal risks caused by the drug treatment of hyperthyroidism during pregnancy.

  • Graves’ disease (GD) is the main pathology etiologically associated with hyperthyroidism in pregnancy.

  • The diagnosis of hyperthyroidism in pregnancy is preferably made by measuring free thyroxine (FT4) and thyroid-stimulating hormone (TSH).

  • The measurement of anti-TSH receptor antibody (TRAb) allows the diagnosis of GD, which is an important cause of hyperthyroidism.

  • Propylthiouracil (PTU) is the first-choice drug for the treatment of hyperthyroidism in pregnancy in the first trimester, while methimazole (MMZ) is used in the second and third trimesters and puerperal period.

  • The use of antithyroid drugs (ATD) is allowed during breastfeeding.

  • Radioactive iodine (131I) should not be used during pregnancy or breastfeeding.

The National Commission Specialized in High Risk Pregnancy of the Brazilian Federation of Gynecology and Obstetrics Associations (Febrasgo) and the Thyroid Department of the Brazilian Society of Endocrinology and Metabology (SBEM) endorse this document. The production of content is based on scientific evidence on the proposed theme and the results presented contribute to clinical practice.

Publication History

Article published online:
08 September 2022

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