A 29-year-old woman comes to the physician for her first antenatal screening. Her last menstrual period was 8 weeks ago. She has been receiving levothyroxine for a 3-year history of Hashimoto thyroiditis. Laboratory studies show thyroid-stimulating hormone (TSH) and free T4 are in the normal range. If the mother’s TSH concentration increases during pregnancy, the fetus is at greatest risk for which of the following?
Abnormal brain development
Congenital deafness
Intrauterine growth restriction
Pituitary apoplexy
Thyroid gland enlargement
