Timing of Graves' Hyperthyroidism Management in Pregnant Women: Impact on the Infant Thyroid Volume

The thyroid of the fetus of a mother with Graves’ disease (GD) is affected by the transplacental passage of both antithyroid drugs (ATDs) and thyroid-stimulating hormone receptor antibodies (TRAb). Thyroid hormone imbalances are harmful for the developing brain. This study aimed to evaluate the impact of the duration of antithyroid drug treatment in hyperthyroid pregnant women with GD on infants’ thyroid volume. Twenty-nine neonates born to mothers with GD were divided into two groups depending on the duration of ATDs treatment. The ultrasound thyroid volumes of the infants were measured within the first week of life. Thyroid-stimulating hormone, thyroxine, and TRAb values were recorded. There was no difference between groups in the thyroid hormones’ values. The median thyroid volume for the entire group of neonates with mothers with GD, for the groups of neonates of mothers with long- and short-treated GD, and for the control group were 1.539, 1.816, 1.347 and 1.014 mL, respectively. There were statistically significant differences in the thyroid volume between the GD group and the control group, as well as between the groups of neonates of mothers with long- and short-treated GD (p < 0.05). Studies have shown that the longer the duration of ATDs administration to mothers, the greater the thyroid volume of the neonate.