Thyroid in Pregnancy

Many changes in the functioning of the thyroid gland occur during pregnancy and some diseases of the thyroid gland can affect both the pregnant woman and the fetus. (Casey et all., 2006; Lazarus & Premawardhana, 2005; Poppe et all., 2007). Hypothyroidism is the most serious disorder of those occurring during pregnancy, and it might go unnoticed as some ‘nonspecific’ problem. Pregnant women with subclinical hypothyroidism seem to escape early clinical detection (Lazarus, 2002). While the hyperfunction during pregnancy usually manifests itself by clinical symptoms or a relapse of a previously cured disease (mostly Graves Basedow) (Abalovich et all., 2007), lowered functioning is much more dangerous because of its non-specific symptoms. During the 1st trimester, the fetus is completely dependent upon thyroxin produced by the mother (Smallridge & Landerson, 2001). Even a small unnoticed malfunction of the thyroid gland, which doesn’t have to endanger the course of the pregnancy, can affect the psychomotor developement of the child (Morreale de Escobar et all., 2004; Mitchell & Klein, 2004)). Some women with subclinical hypothyroidism are absolutely asymptomatic and there is no reliance on the clinical image, while diagnostic of thyroid dysfunction (Klein et all., 2001). Malfunction of the thyroid gland during pregnancy is long-term, and still not a sufficiently solved problem (Lazarus, 2002). On many pages of scientific literature and specialist literature there are still new arguments to systematically screen pregnant women for thyroid dysfunction and asymptomatic chronic thyroiditis in order to give such women the appropriate treatment (Surks et all., 2004). Results of surface population screenings are slightly varied, depending upon on level of medical care and approach to prevention, geographical conditions, supplementing with iodine, and other circumstances (including used diagnostic criteria) (Vaidya et all., 2007). Evaluating thyroidal function during pregnancy is difficult, considering the other differing influences of pregnancy. Guidelines for management of thyroid dysfunction during pregnancy and postpartum (Abalowich et al. 2007) recommend not universal but only case finding screening. The first aim of the study was to assess the value of this recommendation. The other aim was to introduce an estimation of thyroid dysfunction during pregnancy, selection of suitable biochemical markers and determination of reference intervals for these markers in pregnancy.