Endocrine Abstracts

We are presenting a female, aged 34, who underwent two pregnancy miscarriages, in the 7th and 8th weeks. The first studies of thyroid hormones were made during the second pregnancy, and pointed to hyperthyroidism.

After the loss of her second pregnancy, she was diagnosed for thyroid disease and miscarriages. TSH, FT₃, FT₄, antibodies TPO, TG, and TRAB were normal. Ultrasound examination showed symmetrical thyroid, not enlarged, with the presence of heterogeneous small areas in both lobes. Fine-needle biopsy showed benign lesions. In thyroid scintigraphy with the radioisotope technetium there was no evident autonomy.

After half a year, patient reported in the 7th week of third pregnancy with the symptoms of hyperthyroidism. Clinically she presented tachycardia, did not gain weight and vommitted.

Laboratory it was noticed greatly increased thyroid hormones with extremely high hCG: 197 877 mlU/ml concentration in the blood serum. Gynecological ultrasonography showed living fetus corresponding to the 7th week of pregnancy. Chorion showed no signs of detachment. Patient was treated with Propylthiouracil, progesteronum, folic acid and i.v. hydratation.

In the 12th week occurred normalization of hormone levels, a decrease of hCG, antithyroid drug was discontinued. She remains under the care of a gynecologist, endocrinologist, pregnancy is developing normally.

Conclusions: Often at the beginning of the pregnancy occurs hyperthyroidism caused by TSH-like properties of hCG. It was calculated that hCG is ~1/4000 thyrotropic activity of human TSH. The physiological effects of hCG causes hyperthyroidism, but does not lead to pregnancy loss.

In this case, there has been a miscarriage of two successive pregnancies. Therefore we conclude, that a very high concentration of hCG leading to severe thyrotoxicosis may be a causative factor of the pregnancy miscarriages.

In such a situation hypersensitivity to the TSH receptor hCG can not be excluded.