Overview

Poorly controlled maternal hyperthyroidism increases the risk of pregnancy complications (eg miscarriage, premature birth, low birth weight). The goal of management of hyperthyroidism in pregnancy is to maintain maternal euthyroidism, with the maternal serum free thyroxine (T₄) concentration in the upper half of the trimester-specific reference range.

Serum thyroid stimulating hormone (TSH) suppression commonly occurs as a normal part of early pregnancy, and is usually not a cause for concern; see Thyroid function testing before conception and during pregnancy for trimester-specific reference ranges for serum TSH concentration.

Thyrotoxicosis and hyperthyroidism in pregnancy should be managed with specialist input.

Infants of mothers with prior or current Graves disease have a low risk of developing neonatal hyperthyroidism. Thyroid ablation (thyroidectomy or radioiodine) before pregnancy does not eliminate this risk. Specific monitoring is required throughout pregnancy in these women; see Neonatal hyperthyroidism.