The thyrotoxicosis occurs when body tissues are exposed to excessive amounts of thyroid hormones, i.e., the T3 and T4. Thus, the term includes all thyrotoxicosis conditions that increase blood concentrations of these hormones from gland diseases to excessive intake of T3 and / or T4. Already the term hyperthyroidism refers to the increase in hormones due to one's own thyroid disease.

First, it is noteworthy that women with hyperthyroidism may have greater difficulty becoming pregnant. In pregnancy, hyperthyroidism frequency is about 0.05 to 2.9%, which is the most common cause Graves' disease. In this case, the body produces antibodies that stimulate the production of hormones by the gland. The diagnosis of hyperthyroidism is performed by the blood test showing increased levels of T3 and T4 as well as the TSH (thyroid stimulating hormone) below.

The presence of high levels of thyroid hormones duringpregnancy can result in various problems for both the mother and thefetus. Tables 1 and 2 list some complications that canappear, especially when hyperthyroidism is serious.

The elevation of maternal free T4 levels in the blood appears to be the most important factor for the increase in maternal and fetal complications during pregnancy and the neonatal period.

Thus, it is very important that hyperthyroidism in pregnancy isidentified and treated quickly, since the worse the control ofT3 and T4 levels, the greater the risk for complications described.

Forthe early diagnosis possible, the physician should beaware of possible clinical manifestations of hyperthyroidism(Table 3). Depending on the severity, hyperthyroidism can beadequately treated with the lowest possible doses of drugsantithyroid for free T4 levels are maintained within thenormal values ​​and thus reduced risks to the mother and the fetus(Table 1 and 2). If medical treatment is ineffective, or wherethere are adverse effects or even hypersensitivity tomedicine, surgical treatment, in the second trimester of pregnancycan be considered.

Obviously, the best solution would be that pregnancy could be delayed until the hyperthyroidism was resolved. However, for various reasons, making the diagnosis may occur later, only when the woman is already pregnant. In this case, the obstetrician plays a key role, since most of the time, he is the first to identify this problem. Monitoring will then be carried out by endocrinologist throughout pregnancy and even after childbirth, according to the cause of hyperthyroidism.

So when there is suspicion of hyperthyroidism during pregnancy, evaluationthe gland function is indispensable, since the sharp increase ofT3 and T4 in the blood may result in serious consequences maternal and fetal.

Pinheiro AP, Costa AAR Abbade JF, Magellan CG, Mazeto GFS, Hyperthyroidism in pregnancy: maternal-fetal repercussions, Obstet Gynecol. 2008; 30 (9): 452-8.

Maciel LMZ, Magellan PKR. Thyroid and Pregnancy, Arq Bras Endocrinol Metab 2008; 52-7