There is a small chance of an attack of high fever, palpitations, nausea, vomiting and diarrhea. The pregnant can then become confused or even coma. This is rare.
Advice to Women with Hyperthyroidism and Pregnancy Wish
Do you have hyperthyroidism and want to become pregnant? You should discuss this with your GP or specialist (endocrinologist or gynecologist) at the hospital.
Once the amount of thyroid hormone in the blood by treatment back to normal, is it safe to become pregnant.