We present a case of a 30-year-old woman diagnosed with arterial hypertension in the 25th week of pregnancy. Our search for secondary causes of arterial hypertension revealed hyperthyroid Hashimoto's thyroiditis (HT), which was treated with propilthiouracil. Three weeks after delivery, she was normotensive without medication. In the next four months, she developed hypothyroidism and treatment with L-thyroxine was started. In conclusion, in the second half of pregnancy, a hyperthyroid HT can occur - in spite of the well-known amelioration of autoimmune thyroid disorders in that period, and can be the only cause of arterial hypertension.
Keywords: Hashimoto's thyroiditis; hyperthyroidism; pregnancy; systolic arterial hypertension.