Backgrond: The thyroid is a hormone-producing endocrine gland which is located in the front of the throat. The thyroid gland tissue contains several microscopic and spherical cavities called follicles. Thyroid hormones thyroxine (T4) and triiodothyronine (T3) are produced from the follicle cells and regulated by a so-called three-hormone sequence. Thyroid stimulating hormone (TSH) is the second hormone in the sequence and is produced from the pituitary gland. During pregnancy, the thyroid gland produces a greater amount of hormone to cater the needs of the mother and her offspring. When the gland produces too little hormone, it is called hypothyroidism. The disease causes symptoms such as chills, dryness, depression, and hair loss. The disease is divided into different types depending on the underlying cause of the disease. It is called primary hypothyroidism when disorders are in the thyroid gland itself and secondary when the problem is elsewhere in the body, usually in the hypothalamus. Hypothyroidism during pregnancy increases the risk of obstetric complications and can also lead to reduced IQ development in the fetus. Levothyroxine is a synthetic T4 and is used as a first-line drug in the treatment of hypothyroidism. Aim: The aim of this study was to investigate whether treatment with levothyroxine in subclinical hypothyroidism in pregnancy reduces the risk of pregnancy complications and also to analyze how thyroid autoimmunity and subclinical hypothyroidism affect the pregnant woman. Method: The work is a literature study conducted using six relevant published articles retrieved from the medical database and the search engine PubMed. Results: The studies 2,4,5 concluded that subclinical hypothyroidism and thyroid autoimmunity increase the risk of pregnancy complications. Studies 1 and 6 could not show any connection between these groups. Levothyroxine treatment in pregnancy with TSH value greater than 4 mIU/L is effective and leads to reduced risk of miscarriage, admission to neonatal wards and premature birth. In addition, the studies showed that the levothyroxine treatment in patients with TSH value less than 4mIU/L is without any significant effect.   Conclusion: The evidence at present, is unclear and there is insufficient data to determine the efficacy of treatment in patients with TSH levels below 2.5 mIU / L. More and larger clinical randomized controlled trials in pregnant women with subclinical hypothyroidism and positive for thyroperoxidase antibodies are needed to increase the validity of the treatment. In contrast, levothyroxine treatment in mothers with a TSH level in serum greater than 4 mIU / L is effective and of significant importance for both the woman and her offspring.

Syftet med det här arbetet var att undersöka en eventuell koppling mellan subklinisk hypotyreos och depression. De hypoteser som prövas är: ”Värdet för tyreoideastimulerande hormon (TSH) kan användas som markör för depression” samt ”Värdet för antikroppar mot tyreoperoxidas (TPOAk) kan användas som markör för depression”. Metoden som använts är en litteraturstudie. Vetenskapliga artiklar publicerade 2012 och framåt som möter inklusionkriterierna har använts. Dessa kriterier var att artiklarna skulle vara orginalstudier, vetenskapligt granskade, mäta nivåer av TSH och TPOAk i serum samt undersöka sambandet mellan hypotyreos och depression genom att titta på serumnivåer av TSH och TPOAk. Studierna skulle ej vara utförda på djur. Resultatet visar att fyra av sju artiklar påvisar ett positivt samband mellan hypotyreos och depression. Det visar även att tre artiklar kunde påvisa ett positivt samband mellan TSH och depression och tre artiklar kunde påvisa ett positivt samband mellan TPOAk och depression. Slutsatsen är att det verkar finnas ett samband mellan subklinisk hypotyreos och depression samt att TSH och TPOAk inte enskilt utgör markörer för depression men det sammantagna värdet av dem bör kunna ge en indikation på om det finns ett samband eller inte. / The aim of this study was to investigate a possible link between subclinical hypothyroidism and depression. The hypotheses that where being tested are: "the level of thyroid stimulating hormone (TSH) can be used as a marker for depression" and "the level of thyroperoxidase antibodies (TPOAb) can be used as a marker for depression". The method used is a literature review. Scientific articles published in 2012 and forward meeting the criteria for inclusion have been used. These criteria were that the articles would be original, peer-reviewed studies, measuring levels of TSH and TPOAb in serum and examine the link between hypothyroidism and depression by looking at serum levels of TSH and TPOAb. The studies should not be conducted on animals. The results show that four out of seven articles indicate a positive association between hypothyroidism and depression. It also shows that three articles were able to demonstrate a positive association between the TSH and depression and three articles were able to demonstrate a positive association between TPOAb and depression. The conclusion is that there appears to be a link between subclinical hypothyroidism and depression and that the levels of TSH and of TPOAb do not individually represent markers of depression but the overall value of them should be able to give an indication of whether there is a connection or not.

Introduktion. Autoimmun tyreoidit (AITD) är en kronisk autoimmun sjukdom där immunförsvarets antikroppar (ab) attackerar tyreoideaproteinerna tyreoideaperoxidas (TPO) och/eller tyreoglobulin (TG). Studier visar att selentillskott hos patienter med AITD kan minska tyreoideaantikroppar, storleken och antalet noduler hos en förstorad tyreoidea. Syftet med detta arbete var att undersöka hur selentillskott påverkar serumnivåer av TPOab, samt tyreoideahormonnivåer vid AITD.   Metod. Arbetet är en litteraturstudie och därför har metoden varit att samla relevant litteratur genom PubMed med sökningar som ”selenium autoimmune thyroiditis”, ”selenium thyroid” och ”autoimmune thyroiditis”. Bland sökresultaten valdes nio artiklar ut baserat på studiekvalitet, publikationsår och relevans. Bland artiklarna granskades och sammanställdes uppmätta nivåer av TPOab samt tyreoideahormonnivåer, vilka valdes som indikation på effekt utav selentillskott. Resultat. Resultaten var inkonsekventa. Majoriteten av studierna (7 av 9) tydde på att oral administrering av selentillskott effektivt minskade serumkoncentrationerna av TPOab hos patienter med AITD i alla åldersgrupper. De studier som resulterade i störst minskning av TPOab pågick i 3-12 månader. Utav de 9 studerade artiklarna var det endast en studie som inte rapporterade någon som helst positiv klinisk effekt hos patienterna. Två av studierna visade att selen förhindrar vidare försämring av tyreoideans ekogenitet, vilket tyder på att selen kan hejda inflammationsprocessen men ej reversera tyreoideaskadorna den orsakat. Majoriteten av studierna (7 av 9) visade att selentillskott ej ger några signifikanta förändringar i tyreoideahormonerna: TSH, fT4 och fT3. Diskussion. Varför AITD-patienter svarar olika på selenadministrering är ännu okänt, men kan misstänkas bero på selenbehandlingens varaktighet, patienternas intratyroidnivåer av selen vid studiens början, förekomst av jodbrist, samt patienternas ålder och sjukdomsprogression. Slutsats. Att ha adekvata fysiologiska nivåer av selen är av stor vikt för att bevara tyreoideans hälsa och förebygga tyreoidearelaterade sjukdomar. Majoriteten utav de granskade studierna visar att tillskott av selen kan minska antalet TPOab. Selentillskott kan även ha immunrelaterade fördelar men verkar inte påverka nivån tyreoideahormonnivåer. Inga negativa effekter påvisades vid intag av selentillskott vilket gör dess administrering säker. Fler studier behöver dock göras för att fastställa effektiviteten av selentillskott vid AITD. / Introduction. Autoimmune thyroiditis (AITD) is a chronic autoimmune disease in which the immune system's antibodies (ab) attack the thyroid proteins thyroid peroxidase (TPO) and/or thyroglobulin (TG). Studies show that selenium supplementation in patients with AITD can reduce thyroid antibodies and the size and number of nodules in an enlarged thyroid. The purpose of this study was to investigate how selenium supplementation affects the serum levels of thyroid peroxidase antibodies (TPOab) and thyroid hormone levels in autoimmune thyroiditis. Method. This is a literature study and therefore the method has been to gather relevant literature through searches on PubMed such as "selenium autoimmune thyroiditis", "selenium thyroid" and "autoimmune thyroiditis". Among the search results, nine articles were selected based on quality, publication year and relevance. Among the articles, measured levels of TPOab and thyroid hormone levels were examined and compiled, and were chosen as an indication of the effect of selenium supplementation. Results. The results were inconsistent. The majority of the studies (7 of 9) suggest that oral administration of selenium supplements effectively reduced serum concentrations of TPOab in patients with AITD in all age groups. The studies that resulted in the largest decrease in TPOab lasted for 3-12 months. Out of the 9 examined studies, only one study did not report any positive clinical effect in patients. Two of the studies showed that the selenium prevents further impairment of thyroid echogenicity, suggesting that selenium can inhibit the inflammatory process but not reverse the pre-existing thyroid damage it’s caused. The majority of studies (7 out of 9) show that selenium supplementation does not produce significant changes in the thyroid hormones: TSH, fT4 and fT3. Discussion. Why AITD-patients respond differently to selenium administration is still unknown, but it may be due to the duration of selenium treatment, the patients' intrathyroid levels of selenium at the onset of the study, the presence of iodine deficiency, as well as the age and disease progression of the patients. Conclusion. Having adequate physiological levels of selenium is of great importance in preserving thyroid health and preventing thyroid-related diseases. The majority of the studies show that selenium supplementation can reduce the number of TPOab. Selenium supplementation may also have immune related benefits but does not appear to affect the thyroid hormone levels. No adverse effects were observed during selenium supplementation, which makes its administration safe. However, more studies are needed to determine the effectiveness of selenium supplementation for AITD.