A 26-year-old pregnant woman in her 16th week of pregnancy visits the office for a prenatal check-up. The patient has had mild hyperthyroidism for two years due to Graves disease and began taking propylthiouracil when she decided to start to be pregnant. There has been no tremor, palpitations, diarrhea, or heat intolerance in the patient. She has no other medical issues or drug allergies. She supplements her diet with prenatal vitamins. The patient does not smoke, drink alcohol, or use illegal drugs. The temperature is 36.7 C (98 F), the blood pressure is 110/60 mm Hg, and the pulse rate is 88 beats per minute. There is no evidence of lid lag, exophthalmos, or hand tremors on physical examination. Thyroid gland palpation is normal. The heart rate of the fetus is normal. Thyroid hormone levels are within the lab's normal ranges. During this visit, her thyroid treatment is changed from propylthiouracil to methimazole. Switching the patient's therapy at this time is aimed at decreasing which of the following complications?

Question

A 26-year-old pregnant woman in her 16th week of pregnancy visits the office for a prenatal check-up. The patient has had mild hyperthyroidism for two years due to Graves disease and began taking propylthiouracil when she decided to start to be  pregnant. There has been no tremor, palpitations, diarrhea, or heat intolerance in the patient. She has no other medical issues or drug allergies. She supplements her diet with prenatal vitamins. The patient does not smoke, drink alcohol, or use illegal drugs. The temperature is 36.7 C (98 F), the blood pressure is 110/60 mm Hg, and the pulse rate is 88 beats per minute. There is no evidence of lid lag, exophthalmos, or hand tremors on physical examination. Thyroid gland palpation is normal. The heart rate of the fetus is normal. Thyroid hormone levels are within the lab's normal ranges. During this visit, her thyroid treatment is changed from propylthiouracil to methimazole.  Switching the patient's therapy at this time is aimed at decreasing which of the following complications?

Quizplus · Accepted Answer

Eductional Objective: Thionamide antithyroid drugs (for example, propylthiouracil [PTU] and methimazole) are used to reduce thyroid hormone production. Because PTU is hepatotoxic, most patients prefer methimazole. However, because methimazole has teratogenic potential, PTU is preferred in the first trimester of pregnancy.

A 26-Year-Old Pregnant Woman in Her 16th Week of Pregnancy