Gebelik ve Tiroid Hastalıkları
Özet
Gebelik sürecinde tiroid hormonları maternal ve fetal gelişim için kritik bir öneme sahiptir ve tiroid bozuklukları doğurganlık dönemindeki kadınlarda ikinci sıklıkta görülen endokrin patolojidir. Hamilelikle birlikte artan metabolik gereksinimleri karşılamak adına tiroid fonksiyonlarında; östrojen artışına bağlı serum tiroksin bağlayıcı globulin (TBG) yükselmesi, insan koryonik gonadotropini (hCG) etkisiyle geçici TSH düşüklüğü ve idrarla atılım ile fetusa transfer sebebiyle iyot ihtiyacının artması gibi fizyolojik değişiklikler meydana gelir. Fetus ilk 10-12 hafta boyunca tiroid hormonu ihtiyacını tamamen anneden karşıladığından, Türkiye Endokrinoloji ve Metabolizma Derneği (TEMD) gebelik planlayan tüm kadınlara ve gebelere erken dönemde TSH taraması önermektedir. En sık Hashimoto tiroiditine bağlı gelişen hipotiroidi tedavisinde sentetik levotiroksin tercih edilirken ve gebelikte doz artırımı gerekirken; Graves hastalığından kaynaklanan hipertiroidi vakalarında ise ilk trimesterde fetusa zarar vermemek adına propiltiyourasil (PTU) öncelikli olarak tercih edilir. Gebelikte saptanan tiroid nodüllerinde yaklaşım hamile olmayan hastalarla benzerdir ancak tiroid sintigrafisi ve radyoaktif iyot tedavisi gebelikte kesinlikle kontrendikedir. Erken dönemde tanı konulup trimestere özgü referans aralıklarına göre tedavi edilen olgularda erken doğum, preeklampsi, düşük ve bilişsel bozukluk gibi maternal-fetal komplikasyonlar önlenebilmektedir.
Thyroid hormones are critically important for maternal and fetal development during pregnancy, and thyroid disorders represent the second most common endocrinopathy in reproductive-aged women. To meet the increased metabolic demands during pregnancy, significant physiological changes occur in thyroid function, including a rise in serum thyroxine-binding globulin (TBG) driven by increased estrogen levels, transiently suppressed TSH due to human chorionic gonadotropin (hCG) stimulation, and an increased requirement for iodine caused by higher renal clearance and transplacental transfer to the fetus. Because the fetus relies entirely on maternal thyroid hormones for the first 10-12 weeks, the Society of Endocrinology and Metabolism of Turkey (TEMD) recommends routine TSH screening for all pregnant women and those planning a pregnancy. Overt hypothyroidism, most commonly caused by Hashimoto's thyroiditis, is treated with synthetic levothyroxine, requiring a dose increase during pregnancy. Conversely, hyperthyroidism, predominantly driven by Graves' disease, is managed with antithyroid medications, where propylthiouracil (PTU) is preferred in the first trimester to mitigate teratogenic risks. Diagnostic approaches for thyroid nodules in pregnancy mirror those for non-pregnant patients; however, thyroid scintigraphy and radioactive iodine therapies are strictly contraindicated. Prompt diagnosis and trimester-specific reference range management effectively prevent complications such as preterm birth, preeclampsia, miscarriage, and fetal cognitive impairment.
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