| Popis: |
The thyroid gland responds to pregnancy by increasing the production of thyroid hormones to accommodate the metabolic demands in the mother and provide thyroid hormones to the fetus. This process is driven by an estradiol-related increase in thyroid-binding globulin (TBG) and by the action of human chorionic gonadotropin (hCG), which has a structural similarity to thyroid-stimulating hormone (TSH), on the hypothalamic-pituitary-thyroid (HPT) axis. These changes cause a decrease in TSH in the first trimester, a slight decrease in free T3 and T4, and an increase in total T3 and T4. Total T3 and T4 remain elevated throughout pregnancy. TSH and free T3/T4 tend to return close to pre-pregnancy levels after mid-pregnancy. Sufficient iodine intake during pregnancy and lactation is necessary to meet the need for increased thyroid hormone production and provide iodine to the fetus and neonate. Pregnant and lactating women are advised to consume 250 μg/day and 290 μg/day of iodine, respectively. An inadequate supply of thyroid hormone can result in poor pregnancy outcomes and cognitive disability in offspring. Understanding thyroid physiology is critical for all providers who care for pregnant women. |
